CYTYC CORP
8-A12G, 1997-08-29
LABORATORY ANALYTICAL INSTRUMENTS
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<PAGE>
 
                      SECURITIES AND EXCHANGE COMMISSION

                            Washington, D.C. 20549

                                --------------

                                   FORM 8-A


               FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                   PURSUANT TO SECTION 12 (b) OR (g) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

                               CYTYC CORPORATION
- --------------------------------------------------------------------------------
            (Exact name of registrant as specified in its charter)


               Delaware                         02-0407755
       -------------------------           ---------------------
        (State of incorporation               (IRS Employer
         or organization)                   Identification No.)

                    85 Swanson Road, Boxborough, MA  01719
           ---------------------------------------------------------
             (Address of principal executive offices)   (Zip Code)

       Securities to be registered pursuant to Section 12(b) of the Act:

          Title of each class                Name of each exchange on which
          to be so registered                each class is to be registered
          -------------------                ------------------------------

                None                                       N/A

       Securities to be registered pursuant to Section 12(g) of the Act:

                Series A Junior Preferred Stock Purchase Rights
                -----------------------------------------------
                                (Title of Class)


<PAGE>
 
Item 1.   Description of Registrant's Securities to be Registered
          -------------------------------------------------------

          On August 6, 1997, the Board of Directors of Cytyc Corporation (the
"Company") declared a dividend of one preferred stock purchase right (a "Right")
- --------                                                                 -----  
for each outstanding share of the Company's Common Stock to stockholders of
record at the close of business on September 5, 1997 (the "Record Date").  Each
                                                           -----------         
Right entitles the registered holder to purchase from the Company a unit
consisting of one one-hundredth of a share (a "Unit") of Series A Junior
                                               ----                     
Participating Preferred Stock, $.01 par value per share (the "Preferred Stock"),
                                                              ---------------   
at a purchase price of $110 per Unit (the "Purchase Price"), subject to
                                           --------------              
adjustment.  The description and terms of the Rights are set forth in a Rights
Agreement (the "Rights Agreement") between the Company and BankBoston, N.A., as
                ----------------                                               
Rights Agent, a copy of which is filed as Exhibit 4.1 hereto.

          Initially, the Rights will be attached to all Common Stock
certificates representing shares then outstanding, and no separate Rights
Certificates will be distributed.  The Rights will separate from the Common
Stock and a Distribution Date will occur upon the earliest of (i) the close of
business on the tenth day (or such later date as may be determined by action of
the Board (with the concurrence of the majority of the Continuing Directors (as
defined below))) following a public announcement that a person or group of
affiliated or associated persons (an "Acquiring Person") has acquired, or
                                      ----------------                   
obtained the right to acquire, beneficial ownership of 15% or more of the
outstanding shares of Common Stock (the "Stock Acquisition Date"), (ii) the
                                         ----------------------            
close of business on the tenth business day (or such later date as may be
determined by action of the Board (with the concurrence of the majority of the
Continuing Directors)) following the commencement of a tender offer or exchange
offer that may result in a person or group beneficially owning 15% or more of
such outstanding shares of Common Stock or (iii) the close of business on the
tenth business day after the Continuing Directors (with the concurrence of the
Independent Directors) of the Company shall declare any Person to be an Adverse
Person, upon a determination that such Person, alone or together with its
affiliates and associates, has become the Beneficial Owner of an amount of
Common Stock which the Continuing Directors determine to be substantial (which
amount shall in no event be less than 10% of the shares of Common Stock then
outstanding) and a majority of the Continuing Directors (with the concurrence of
a majority of the Independent Directors (as defined below)) determines, after
reasonable inquiry and investigation, including consultation with such persons
as such directors shall deem appropriate, that (a) such beneficial ownership by
such person is intended to cause the Company to repurchase the Common Stock
beneficially owned by such person or to cause pressure on the Company to take
action or enter into a transaction or series of transactions intended to provide
such person with short-term financial gain under circumstances where such
directors determine that the best long-term interests of the Company and its
stockholders would not be served by taking such action or entering into such
transaction or series of transactions at that time or (b) such beneficial
ownership is causing or is reasonably likely to cause a material adverse impact
(including, but not limited to, impairment of relationships with customers,
impairment of the Company's ability to maintain its competitive position or
impairment of the Company's business 

<PAGE>
 
reputation or ability to deal with government agencies) on the business or
prospects of the Company.

          Until the Distribution Date (or earlier redemption or expiration of
the Rights), (i) the Rights will be evidenced by the Common Stock certificates
and will be transferred with and only with such Common Stock certificates, (ii)
new Common Stock certificates issued after the Record Date will contain a legend
incorporating the Rights Agreement by reference and (iii) the surrender for
transfer of any certificates for Common Stock outstanding, even without such
legend, will also constitute the transfer of the Rights associated with the
Common Stock represented by such certificate.  Pursuant to the Rights Agreement,
the Company reserves the right to require prior to the occurrence of a
Triggering Event (as defined below) that, upon any exercise of Rights, a number
of Rights may be exercised so that only whole shares of Preferred Stock will be
issued.

          The Rights are not exercisable until the Distribution Date and will
expire at the close of business on September 5, 2007,  unless earlier redeemed
by the Company as described below.

          As soon as practicable after the Distribution Date, separate
certificates evidencing the Rights ("Rights Certificates") will be mailed to
                                     -------------------                    
holders of record of the Common Stock as of the close of business on the
Distribution Date and, thereafter, such separate Rights Certificates alone will
represent the Rights.  Except as otherwise determined by the Board of Directors
and except in connection with shares of Common Stock issued upon the exercise of
employee stock options, issuances under other employee stock benefit plans or
upon the conversion of convertible securities issued hereafter, only shares of
Common Stock issued prior to the Distribution Date will be issued with Rights.

          In the event that the Continuing Directors determine that a person is
an Adverse Person or, at any time following the Distribution Date, (i) the
Company is the surviving corporation in a merger with an Acquiring Person and
its Common Stock is not changed or exchanged, (ii) a Person becomes the
beneficial owner of 20% or more of the then outstanding shares of Common Stock
(except pursuant to an offer for all outstanding shares of Common Stock which a
majority of the Independent Directors determine to be fair to, and otherwise in
the best interests of, the Company and its stockholders), (iii) an Acquiring
Person engages in one or more "self-dealing" transactions as set forth in the
Rights Agreement, or (iv) during such time as there is an Acquiring Person, an
event occurs which results in such Acquiring Person's ownership interest being
increased by more than 1% (e.g., a reverse stock split), each holder of a Right
will thereafter have the right to receive, upon exercise, that number of shares
of Common Stock (or, in certain circumstances, cash, property or other
securities of the Company) which equals the exercise price of the Right divided
by one-half of the current market price (as defined in the Rights Agreement) of
the Common Stock at the date of the occurrence of the event.  However, Rights
are not exercisable following the occurrence of any of the events set forth
above until such time as the Rights are no longer redeemable by the Company as
set forth below.  Notwithstanding any of the foregoing, following the occurrence
of any of 

<PAGE>
 
the events set forth in this paragraph, all Rights that are, or (under certain
circumstances specified in the Rights Agreement were, beneficially owned by an
Acquiring Person or an Adverse Person will be null and void. The events set
forth in this paragraph are described in Section 11(a)(ii) of the Rights
Agreement and are referred to as "Section 11(a)(ii) Events."

          In the event that, at any time following the Stock Acquisition Date,
(i) the Company is acquired in a merger or other business combination
transaction in which the Company is not the surviving corporation (other than a
merger which follows an offer determined by the Board of Directors to be fair as
described in clause (ii) of the second preceding paragraph), or (ii) more than
50% of the Company's assets or earning power is sold or transferred, each holder
of a Right (except Rights which previously have been voided as set forth above)
shall thereafter have the right to receive, upon exercise, that number of shares
of common stock of the acquiring company which equals the exercise price of the
Right divided by one-half of the current market price (as defined in the Rights
Agreement) of such common stock at the date of the occurrence of the event.  The
events set forth in this paragraph and in the preceding paragraph are referred
to as the "Triggering Events."
           -----------------  

          At any time after the occurrence of a Section 11(a)(ii) Event, the
Board (with the concurrence of a majority of the Continuing Directors) may
exchange the Rights (other than Rights owned by an Acquiring Person or Adverse
Person which have become void), in whole or in part, at an exchange ratio of one
share of Common Stock, or one Common Stock Equivalent (as defined in the Rights
Agreement), per Right (subject to adjustment).

          The Purchase Price payable, and the number of Units of Preferred Stock
or other securities or property issuable, upon exercise of the Rights are
subject to adjustment from time to time to prevent dilution (i) in the event of
a stock dividend on, or a subdivision, combination or reclassification of, the
Preferred Stock, (ii) if holders of the Preferred Stock are granted certain
rights or warrants to subscribe for Preferred Stock or convertible securities at
less than the current market price of the Preferred Stock, or (iii) upon the
distribution to holders of the Preferred Stock of evidences of indebtedness or
assets (excluding regular quarterly cash dividends) or of subscription rights or
warrants (other than those referred to above).

          With certain exceptions, no adjustment in the Purchase Price will be
required until cumulative adjustments amount to at least 1% of the Purchase
Price.  No fractional Units will be issued and, in lieu thereof, an adjustment
in cash will be made based on the market price of the Preferred Stock on the
last trading date prior to the date of exercise.

          In general, the Company may redeem the Rights in whole, but not in
part, at any time until ten days following the Stock Acquisition Date, at a
price of $.01 per Right (payable in cash, Common Stock or other consideration
deemed appropriate by the Board of Directors).  Under certain circumstances set
forth in the Rights Agreement, the decision to redeem shall require the
concurrence of a majority of the Continuing 

<PAGE>
 
Directors. The Company may not redeem the Rights if the Continuing Directors
have previously declared a person to be an Adverse Person. Immediately upon the
action of the Board of Directors ordering redemption of the Rights, with, where
required, the concurrence of the Continuing Directors, the Rights will terminate
and the only right of the holders of Rights will be to receive the $.01 per
Right redemption price.

          The term "Continuing Directors" means any member of the Board of
                    --------------------                                  
Directors of the Company who was a member of the Board of directors on the date
of the Rights Agreement, and any person who is subsequently elected to the Board
of Directors if such person is recommended or approved by a majority of the
Continuing Directors, but shall not include an Acquiring Person, an Adverse
Person or an affiliate or associate of an Acquiring Person or an Adverse Person,
or any representative of the foregoing entities.  The term "Independent
                                                            -----------
Directors" means Continuing Directors who are not officers of the Company.
- ---------                                                                 

          Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the Company, including, without limitation, the right
to vote or to receive dividends.  While the distribution of the Rights will not
be taxable to stockholders or to the Company, stockholders may, depending upon
the circumstances, recognize taxable income in the event that the Rights become
exercisable for Common Stock (or other consideration) of the Company or for
common stock of the acquiring company as set forth above.

          The provisions of the Rights Agreement may be amended by the Board of
Directors of the Company prior to the earlier to occur of the determination that
a person is an Adverse Person or the Distribution Date.  After the earlier of
such events, the provisions of the Rights Agreement may be amended by the Board
of Directors (in certain circumstances, with the concurrence of the Continuing
Directors) in order to cure any ambiguity, to make changes which do not
adversely affect the interests of holders of Rights (excluding the interests of
any Acquiring Person or any Adverse Person), or to shorten or lengthen any time
period under the Rights Agreement; provided, however, that no amendment to
                                   --------  -------                      
adjust the time period governing redemption shall be made at such time as the
Rights are not redeemable.

Item 2.  Exhibits
         --------

<TABLE>
<CAPTION>
        Exhibit No.          Exhibit
        -----------          -------
<S>                          <C>
             1               Rights Agreement, dated as of August 27, 1997,
                             between Cytyc Corporation and BankBoston, N.A.,
                             which includes as Exhibit A the Form of
                             Certificate of Designations, as Exhibit B the Form
                             of Rights Certificate, and as Exhibit C the
                             Summary of Rights to Purchase Preferred Stock.
</TABLE>

<PAGE>
 
                                   SIGNATURE
                                   ---------

          Pursuant to the requirements of Section 12 of the Securities Exchange
Act of 1934, the Registrant has duly caused this registration statement to be
signed on its behalf by the undersigned, thereto duly authorized.

                                        CYTYC CORPORATION


                                        By:   /s/ Joseph W. Kelly     
                                           ----------------------------   
                                           Joseph W. Kelly
                                           Chief Financial Officer


Dated:  August 29, 1997


<PAGE>
 
                                 Exhibit Index

<TABLE> 
<CAPTION> 

                                                               
 Exhibit                                                       
 Number            Description                                
 ------            -----------                                
<S>         <C>                                               
   1        Rights Agreement, dated as of August 27, 1997,
            between Cytyc Corporation and BankBoston, N.A., 
            which includes as Exhibit A the Form of 
            Certificate of Designations, as Exhibit B the 
            Form of Rights Certificate, and as Exhibit C 
            the Summary of Rights to Purchase Preferred 
            Stock.
</TABLE> 



<PAGE>
 
                                                                       Exhibit 1

- --------------------------------------------------------------------------------




                               CYTYC CORPORATION

                                      and

                               BANKBOSTON, N.A.

                                as Rights Agent

                                  ----------

                               RIGHTS AGREEMENT

                          Dated as of August 27, 1997




- --------------------------------------------------------------------------------
<PAGE>
 
                               Table of Contents
                               -----------------
<TABLE>
<CAPTION>
 
Section                                                                     Page
- -------                                                                     ----

<S>                                                                         <C>
  1.  Certain Definitions.....................................................1

  2.  Appointment of Rights Agent.............................................6

  3.  Issue of Rights Certificates............................................7

  4.  Form of Rights Certificates.............................................8

  5.  Countersignature and Registration.......................................9

  6.  Transfer, Split Up, Combination and Exchange of Rights Certificates;
      Mutilated, Destroyed, Lost or Stolen Rights Certificates...............10

  7.  Exercise of Rights; Purchase Price; Expiration Date of Rights..........11

  8.  Cancellation and Destruction of Rights Certificates....................13

  9.  Reservation and Availability of Capital Stock..........................13

  10. Preferred Stock Record Date............................................14

  11. Adjustment of Purchase Price, Number and Kind of Shares or Number of
      Rights.................................................................15

  12. Certificate of Adjusted Purchase Price or Number of Shares.............24

  13. Consolidation, Merger or Sale or Transfer of  Assets or Earning
      Power..................................................................24

  14. Fractional Rights and Fractional Shares................................27

  15. Rights of Action.......................................................28

  16. Agreement of Rights Holders............................................28

  17. Rights Certificate Holder Not Deemed a Stockholder.....................29

  18. Concerning the Rights Agent............................................29

  19. Merger or Consolidation or Change of Name of Rights Agent..............30

  20. Duties of Rights Agent.................................................30

  21. Change of Rights Agent.................................................32

  22. Issuance of New Rights Certificates....................................33
</TABLE> 
<PAGE>
 
<TABLE> 
  <S>                                                                        <C>
  23. Redemption and Termination..............................................33

  24. Exchange................................................................34

  25. Notice of Certain Events................................................36

  26. Notices.................................................................36

  27. Supplements and Amendments..............................................37

  28. Successors..............................................................38

  29. Determinations and Actions by the Board of Directors, etc...............38

  30. Benefits of this Agreement..............................................38

  31. Severability............................................................39

  32. Governing Law...........................................................39

  33. Counterparts............................................................39

  34. Descriptive Headings....................................................39
</TABLE>


Exhibit A -- Form of Certificate of Designations of Preferred Stock

Exhibit B -- Form of Rights Certificate

Exhibit C -- Form of Summary of Rights
<PAGE>
 
                                RIGHTS AGREEMENT
                                ----------------



       RIGHTS AGREEMENT, dated as of August 27, 1997 (the "Agreement"), between
                                                           ---------
CYTYC CORPORATION, a Delaware corporation (the "Company"), and BANKBOSTON, N.A.,
                                                -------
as Rights Agent (the "Rights Agent").
                      ------------

                                   WITNESSETH

       WHEREAS, on August 6, 1997 (the "Rights Dividend Declaration Date"), the
                                        --------------------------------
Board of Directors of the Company (the "Board") authorized and declared a
                                        -----
dividend distribution of one Right for each share of Common Stock (as
hereinafter defined) of the Company outstanding at the close of business on
September 5, 1997, (the "Record Date"), and has authorized the issuance of one
                         -----------
Right (as such number may hereinafter be adjusted pursuant to the provisions of
Section 11(a)(i) hereof) for each share of Common Stock of the Company issued
(whether originally issued or delivered from the Company's treasury) between the
Record Date and the Distribution Date, each Right initially representing the
right to purchase one one-hundredth of a share of Series A Junior Participating
Preferred Stock upon the terms and conditions hereinafter set forth (the
"Rights");
 ------

       NOW, THEREFORE, in consideration of the premises and the mutual
agreements herein set forth, the parties hereby agree as follows:

       Section 1. Certain Definitions. For purposes of this Agreement, the
                  -------------------
following terms have the meanings indicated:

              (a)    "Acquiring Person" shall mean any Person who or which,
                      ----------------
together with all Affiliates and Associates of such Person, shall be the
Beneficial Owner of 15% or more of the shares of Common Stock then outstanding,
but shall not include the Company, any Subsidiary of the Company, any employee
benefit plan of the Company or of any Subsidiary of the Company, or any Person
or entity organized, appointed or established by the Company for or pursuant to
the terms of any such plan. Notwithstanding the foregoing, no Person shall
become an "Acquiring Person" as the result of an acquisition of Common Stock by
the Company which, by reducing the number of shares outstanding, increases the
proportionate number of shares beneficially owned by such Person to 15% or more
of the Common Stock of the Company then outstanding; provided, however, that if
                                                     --------  -------
a Person shall become the Beneficial Owner of 15% or more of the Common Stock of
the Company then outstanding by reason of share purchases by the Company and
shall, after such share purchases by the Company, become the Beneficial Owner of
any additional Common Stock of the Company, then such Person shall be deemed to
be an "Acquiring Person." Notwithstanding the foregoing, if the Board, with the
consent of a majority of the Continuing Directors, determines in good faith that
a Person who would otherwise be an "Acquiring Person," as defined pursuant to
the foregoing provisions of this paragraph (a), has become such inadvertently,
and such Person divests as promptly as practicable a sufficient number of shares
of Common Stock so that such Person would no longer be an 
<PAGE>
 
"Acquiring Person," as defined pursuant to the foregoing provisions of this
paragraph (a), then such Person shall not be deemed to be an "Acquiring Person"
for any purposes of this Agreement.

              (b)    "Act" shall mean the Securities Act of 1933, as amended.
                      ---

              (c)    "Adjustment Shares" shall have the meaning set forth in
                      -----------------
Section 11(a)(ii)(D) hereof.

              (d)    "Adverse Person" shall mean any Person declared to be an
                      --------------
Adverse Person by the Continuing Directors upon determination that the criteria
set forth in Section 11(a)(ii)(D) hereof apply to such Person.

              (e)    "Adverse Person Event" shall mean the determination by
                      --------------------
the Continuing Directors (with the concurrence of the Independent Directors),
pursuant to Section 11(a)(ii)(D) hereof, that a Person is an Adverse Person.

              (f)    "Affiliate" and "Associate" shall have the respective 
                      ---------       ---------
meanings ascribed to such terms in Rule 12b-2 of the General Rules and
Regulations under the Securities Exchange Act of 1934, as amended and in effect
on the date of this Agreement (the "Exchange Act").
                                    ------------   

              (g)    "Agreement" shall mean this Rights Agreement as originally
                      ---------
executed or as it may from time to time be supplemented or amended pursuant to
the applicable provisions hereof.

              (h)    A Person shall be deemed the "Beneficial Owner" and shall
                                                   ----------------
be deemed to "beneficially own", any securities:
              ----------------                  

              (i)    which such Person or any of such Person's Affiliates or
                     Associates, directly or indirectly, has the right to
                     acquire (whether such right is exercisable immediately or
                     only after the passage of time) pursuant to any agreement,
                     arrangement or understanding, whether or not in writing, or
                     upon the exercise of conversion rights, exchange rights,
                     other rights, warrants or options, or otherwise; provided,
                                                                      --------
                     however, that a Person shall not be deemed the "Beneficial
                     -------
                     Owner" of, or to "beneficially own", (A) securities
                     tendered pursuant to a tender offer or exchange offer made
                     by such Person or any of such Person's Affiliates or
                     Associates until such tendered securities are accepted for
                     purchase or exchange, or (B) securities issuable upon
                     exercise of Rights at any time prior to the occurrence of a
                     Triggering Event, or (C) securities issuable upon exercise
                     of Rights from and after the occurrence of a Triggering
                     Event which Rights were acquired by such Person or any of
                     such Person's Affiliates or Associates prior to the
                     Distribution Date or pursuant to Section 3(a) or Section 22
                     hereof (the "Original Rights") or pursuant to 
                                  ---------------
                     Section 11(a)(i)

                                      -2-
<PAGE>
 
                     hereof in connection with an adjustment made with respect
                     to any Original Rights;

              (ii)   which such Person or any of such Person's Affiliates or
                     Associates, directly or indirectly, has the right to vote
                     or dispose of or has "beneficial ownership" of (as
                     determined pursuant to Rule 13d-3 of the General Rules and
                     Regulations under the Exchange Act, or any comparable or
                     successor rule), including pursuant to any agreement,
                     arrangement or understanding, whether or not in writing;
                     provided, however, that a Person shall not be deemed the
                     --------  -------
                     "Beneficial Owner" of, or to "beneficially own", any
                     security under this subparagraph (ii) as a result of an
                     agreement, arrangement or understanding to vote such
                     security if such agreement, arrangement or understanding:
                     (A) arises solely from a revocable proxy given in response
                     to a public proxy or consent solicitation made pursuant to,
                     and in accordance with, the applicable provisions of the
                     General Rules and Regulations under the Exchange Act, and
                     (B) is not also then reportable by such Person on Schedule
                     13D under the Exchange Act (or any comparable or successor
                     report); or

              (iii)  which are beneficially owned, directly or indirectly, by
                     any other Person (or any Affiliate or Associate thereof)
                     with which such Person (or any of such Person's Affiliates
                     or Associates) has any agreement, arrangement or
                     understanding, whether or not in writing, for the purpose
                     of acquiring, holding, voting (except pursuant to a
                     revocable proxy as described in the proviso to subparagraph
                     (ii) of this paragraph (h)) or disposing of any voting
                     securities of the Company (a joint filing of a Schedule 13D
                     under the Exchange Act or any comparable or successor
                     report being deemed to be conclusive evidence of such an
                     agreement, arrangement or understanding);

provided, however, that nothing in this paragraph (h) shall cause a Person
- --------  -------                                                         
engaged in business as an underwriter of securities to be the "Beneficial Owner"
of, or to "beneficially own", any securities acquired through such Person's
participation in good faith in a firm commitment underwriting until the
expiration of forty days after the date of such acquisition.  Notwithstanding
anything in this definition of Beneficial Ownership to the contrary, the phrase
"then outstanding," when used with reference to a Person's Beneficial Ownership
of securities of the Company, shall mean the number of such securities then
issued and outstanding together with the number of such securities not then
actually issued and outstanding which such Person would be deemed to own
beneficially hereunder.

              (i)    "Board" means the Board of Directors of the Company.
                      -----                                              

              (j)    "Business Day" shall mean any day other than a Saturday,
                      ------------
Sunday or a day on which banking institutions in the Commonwealth of
Massachusetts are authorized or obligated by law or executive order to close.

                                      -3-
<PAGE>
 
              (k)    "Close of Business" on any given date shall mean 5:00 P.M.,
                      -----------------
Boston time, on such date; provided, however, that if such date is not a
                           --------  -------
Business Day it shall mean 5:00 P.M., Boston time, on the next succeeding
Business Day.

              (l)    "Common Stock" shall mean the common stock, $.01 par value
                      ------------
per share, of the Company, provided, however, that "Common Stock" when used with
reference to any Person other than the Company shall mean the capital stock of
such Person with the greatest voting power, or the equity securities or other
equity interest having power to control or direct the management, of such
Person.

              (m)    "Common Stock Equivalents" shall have the meaning set forth
                      ------------------------
in Section 11(a)(iii) hereof.

              (n)    "Company" shall mean the Person named as the "Company" in
                      -------
the first paragraph of this Agreement until a successor corporation shall have
become such or until a Principal Party shall assume, and thereafter be liable
for, all obligations and duties of the Company hereunder, pursuant to the
applicable provisions of this Agreement, and thereafter "Company" shall mean
such successor corporation or Principal Party.

              (o)    "Continuing Director" shall mean (i) any member of the 
                      -------------------
Board, while such Person is a member of the Board, who is not an Acquiring
Person or an Adverse Person, or an Affiliate or Associate of such Person, or a
representative of such Person or of any such Affiliate or Associate, and was a
member of the Board on the date of this Agreement, or (ii) any Person who
becomes a member of the Board subsequent to the date of this Agreement, while
such Person is a member of the Board, who is not an Acquiring Person or an
Adverse Person, or an Affiliate or Associate of such Person, or a representative
of an Acquiring Person or an Adverse Person or of any such Affiliate or
Associate, if such Person's nomination for election or election to the Board is
recommended or approved by a majority of the Continuing Directors.

              (p)    "Current Market Price" shall have the meaning set forth in
                      --------------------
Section 11(d)(i) hereof.

              (q)    "Current Value" shall have the meaning set forth in 
                      -------------
Section 11(a)(iii) hereof.

              (r)    "Distribution Date" shall have the meaning set forth in 
                      -----------------
Section 3(a) hereof.

              (s)    "Equivalent Preferred Stock" shall have the meaning set 
                      --------------------------
forth in Section 11(b) hereof.

              (t)    "Exchange Act" shall have the meaning set forth in 
                      ------------
Section 1(f) hereof.

              (u)    "Expiration Date" shall have the meaning set forth in 
                      ---------------
Section 7(a) hereof.

                                      -4-
<PAGE>
 
              (v)    "Final Amendment Date" shall mean the earlier of the
                      --------------------
Distribution Date or the occurrence of an Adverse Person Event.

              (w)    "Final Expiration Date" shall mean the close of business on
                      ---------------------                                     
September 5, 2007.

              (x)    "Independent Directors" shall mean the Continuing Directors
                      ---------------------
who are not officers of the Company.

              (y)    "Initial Exercise Price" shall be $110.
                      ----------------------                

              (z)    "Nasdaq" shall mean the National Association of Securities
                      ------                                                   
Dealers, Inc. Automated Quotation System.

              (aa)   "Original Rights" shall have the meaning set forth in 
                      ---------------
Section 1(h)(i) hereof.

              (bb)   "Person" shall mean any natural person, firm, association,
                      ------                                                   
corporation, partnership, trust or other entity or organization.

              (cc)   "Preferred Stock" shall mean the Series A Junior 
                      ---------------
Participating Preferred Stock, $.01 par value per share, of the Company having
the terms set forth in the form of certificate of designation attached hereto as
Exhibit A.
- ---------

              (dd)   "Principal Party" shall have the meaning set forth in 
                      ---------------
Section 13(b) hereof.

              (ee)   "Purchase Price" shall have the meaning set forth in 
                      --------------
Section 4(a) hereof.

              (ff)   "Record Date" shall have the meaning set forth in the 
                      -----------
preamble of the Agreement.

              (gg)   "Redemption Price" shall have the meaning set forth in 
                      ----------------
Section 23(a) hereof.

              (hh)   "Rights" shall have the meaning set forth in the preamble
                      ------
of the Agreement.

              (ii)   "Rights Agent" shall mean the Person named as the "Rights
                      ------------
Agent" in the first paragraph of this Agreement until a successor Rights Agent
shall have become such pursuant to the applicable provisions hereof, and
thereafter "Rights Agent" shall mean such successor Rights Agent. If at any time
there is more than one Person appointed by the Company as Rights Agent pursuant
to the applicable provisions of this Agreement, "Rights Agent" shall mean and
include each such Person.

              (jj)   "Rights Certificates" shall have the meaning set forth in
                      -------------------
Section 3(a) hereof.


                                      -5-
<PAGE>
 
              (kk)   "Rights Dividend Declaration Date" shall have the meaning
                      --------------------------------
set forth in the preamble of this agreement.

              (ll)   "Section 11(a)(ii) Event" shall mean any event described in
                      -----------------------                                   
Section 11(a)(ii)(A), (B), (C) or (D) hereof.

              (mm)   "Section 11(a)(ii) Trigger Date" shall have the meaning set
                      ------------------------------
forth in Section 11(a)(iii) hereof.

              (nn)   "Section 13 Event" shall mean any event described in 
                      ----------------
clauses (x), (y) or (z) of Section 13(a) hereof.

              (oo)   "Spread" shall have the meaning set forth in 
                      ------
Section 11(a)(iii) hereof.

              (pp)   "Stock Acquisition Date" shall mean the first date of a 
                      ----------------------
public announcement (which, for purposes of this definition, shall include,
without limitation, a report filed pursuant to Section 13(d) under the Exchange
Act) by the Company or an Acquiring Person that an Acquiring Person has become
such.

              (qq)   "Subsidiary" shall mean, with reference to any Person, 
                      ----------
including the Company, any corporation (or other entity) of which an amount of
voting securities sufficient to elect at least a majority of the directors (or
their equivalent) of such corporation (or other entity) is beneficially owned,
directly or indirectly, by such Person, or which is otherwise controlled by such
Person.

              (rr)   "Substitute Consideration" shall have the meaning set 
                      ------------------------
forth in Section 11(a)(iii) hereof.

              (ss)   "Substitution Period" shall have the meaning set forth in
                      -------------------
Section 11(a)(iii) hereof.

              (tt)   "Trading Day" shall have the meaning set forth in 
                      -----------
Section 11(d) hereof.

              (uu)   "Triggering Event" shall mean any Section 11(a)(ii) Event
                      ----------------
or any Section 13 Event.

       Section 2. Appointment of Rights Agent. The Company hereby appoints the
                  --------------------------- 
Rights Agent to act as agent for the Company and the holders of the Rights (who,
in accordance with Section 3 hereof, shall prior to the Distribution Date also
be the holders of the Common Stock) in accordance with the terms and conditions
hereof, and the Rights Agent hereby accepts such appointment. The Company may
from time to time appoint such co-Rights Agents as it may deem necessary or
desirable.

                                      -6-
<PAGE>
 
       Section 3. Issue of Rights Certificates.
                  ----------------------------

              (a)    Until the earliest of (i) the Close of Business on the
tenth day (or such later date as may be determined by action of the Board (with
the concurrence of a majority of the Continuing Directors)) after the Stock
Acquisition Date (or, if the tenth day after the Stock Acquisition Date occurs
before the Record Date, the Close of Business on the Record Date), (ii) the
Close of Business on the tenth Business Day (or, if such tenth Business Day
occurs before the Record Date, the Close of Business on the Record Date), or
such later date as may be determined by action of the Board (with the
concurrence of a majority of the Continuing Directors), after the date that a
tender offer or exchange offer by any Person (other than the Company, any
Subsidiary of the Company, any employee benefit plan of the Company or of any
Subsidiary of the Company, or any Person or entity organized, appointed or
established by the Company for or pursuant to the terms of any such plan) is
first published or sent or given within the meaning of Rule 14d-2(a) of the
General Rules and Regulations under the Exchange Act, if upon consummation
thereof for the maximum number of shares that may be purchased thereunder, such
Person would be the Beneficial Owner of 15% or more of the shares of Common
Stock then outstanding or (iii) the Close of Business on the tenth Business Day
after an Adverse Person Event (the earliest of (i), (ii) and (iii) being herein
referred to as the "Distribution Date"), (x) the Rights will be evidenced
                    -----------------
(subject to the provisions of paragraph (b) of this Section 3) by the
certificates for the Common Stock registered in the names of the holders of the
Common Stock (which certificates for Common Stock shall be deemed also to be
certificates for Rights) and not by separate certificates, and (y) the Rights
will be transferable only in connection with the transfer of the underlying
shares of Common Stock (including a transfer to the Company). As soon as
practicable after the Distribution Date, the Rights Agent will send by first-
class, insured, postage prepaid mail, to each record holder of the Common Stock
as of the Close of Business on the Distribution Date, at the address of such
holder shown on the records of the Company, one or more rights certificates, in
the form specified in Section 4 hereof (the "Rights Certificates"), evidencing
                                             -------------------
one Right for each share of Common Stock so held, subject to adjustment as
provided herein. In the event that an adjustment in the number of Rights per
share of Common Stock has been made pursuant to Section 11(a)(i) hereof, at the
time of distribution of the Rights Certificates, the Company shall make the
necessary and appropriate rounding adjustments (in accordance with Section 14(a)
hereof) so that Rights Certificates representing only whole numbers of Rights
are distributed and cash is paid in lieu of any fractional rights. As of and
after the Distribution Date, the Rights will be evidenced solely by such Rights
Certificates.

              (b)    As promptly as practicable following the Record Date, the
Company will send to each record holder of the Common Stock as of the Close of
Business on the Record Date, a copy of a Summary of Rights, in substantially the
form attached hereto as Exhibit C, by either first-class, postage prepaid mail
                        ---------
or together with any other information then being delivered by the Company or
its representatives to such holders, at the address of such holder shown on the
records of the Company. With respect to certificates for the Common Stock
outstanding as of the Record Date, until the Distribution Date, the Rights will
be evidenced by such certificates for the Common Stock and the registered
holders of the Common Stock shall also be the registered holders of the
associated Rights. Until the earlier of the Distribution Date or the Expiration
Date (as such term is defined in Section 7 hereof), the transfer of any
certificates representing shares of 

                                      -7-
<PAGE>
 
Common Stock in respect of which Rights have been issued shall also constitute
the transfer of the Rights associated with such shares of Common Stock.

              (c)    Rights shall be issued in respect of all shares of Common
Stock that are issued (whether originally issued or from the Company's treasury)
after the Record Date but prior to the earlier of the Distribution Date or the
Expiration Date. Rights shall also be issued to the extent provided in 
Section 22 in respect of all shares of Common Stock which are issued (whether
originally issued or from the Company's treasury) after the Distribution Date
and prior to the Expiration Date. Certificates representing such shares of
Common Stock in respect of which Rights are issued pursuant to the first
sentence of this Section 3(c) shall also be deemed to be certificates for
Rights, and commencing as soon as reasonably practicable following the date
hereof shall bear the following legend:

       This certificate also evidences and entitles the holder hereof to certain
       Rights as set forth in the Rights Agreement between Cytyc Corporation
       (the "Company") and BankBoston, N.A. (the "Rights Agent") dated as of
       August 27, 1997 (the "Rights Agreement"), the terms of which are hereby
       incorporated herein by reference and a copy of which is on file at the
       principal offices of the Company.  Under certain circumstances, as set
       forth in the Rights Agreement, such Rights will be evidenced by separate
       certificates and will no longer be evidenced by this certificate.  The
       Company will mail to the holder of this certificate a copy of the Rights
       Agreement, as in effect on the date of mailing, without charge promptly
       after receipt of a written request therefor.  Under certain circumstances
       set forth in the Rights Agreement, Rights issued to, or held by, any
       Person who is, was or becomes an Acquiring Person, an Adverse Person or
       any Affiliate or Associate of an Acquiring Person or an Adverse Person
       (as such terms are defined in the Rights Agreement), whether currently
       held by or on behalf of such Person or by any subsequent holder, may
       become null and void.  The Rights shall not be exercisable, and shall be
       void so long as held, by a holder in any jurisdiction where the requisite
       qualification to the issuance to such holder, or the exercise by such
       holder, of the Rights in such jurisdiction shall not have been obtained
       or obtainable.

With respect to such certificates containing the foregoing legend, until the
earlier of (i) the Distribution Date or (ii) the Expiration Date, the Rights
associated with the Common Stock represented by such certificates shall be
evidenced by such certificates alone and registered holders of Common Stock
shall also be the registered holders of the associated Rights, and the transfer
of any of such certificates shall also constitute the transfer of the Rights
associated with the Common Stock represented by such certificates.

       Section 4. Form of Rights Certificates.
                  ---------------------------

              (a)    The Rights Certificates (and the forms of election to
purchase and of assignment to be printed on the reverse thereof) shall each be
substantially in the form set forth in Exhibit B hereto and may have such marks
                                       ---------
of identification or designation and such legends, 

                                      -8-
<PAGE>
 
summaries or endorsements printed thereon as the Company may deem appropriate
and as are not inconsistent with the provisions of this Agreement, or as may be
required to comply with any applicable law or with any rule or regulation made
pursuant thereto or with any rule or regulation of any stock exchange or trading
market on which the Rights may from time to time be listed or traded, or to
conform to usage. Subject to the provisions of Section 11 and Section 22 hereof,
the Rights Certificates, whenever distributed, shall be dated as of the Record
Date and on their face shall entitle the holders thereof to purchase such number
of one one-hundredths of a share of Preferred Stock as shall be set forth
therein at the price per share set forth therein (such exercise price per one
one-hundredth of a share hereinafter referred to as the "Purchase Price"), but
                                                         --------------
the amount and type of securities purchasable upon the exercise of each Right
and the Purchase Price thereof shall be subject to adjustment as provided
herein.

              (b)    Any Rights Certificate issued pursuant to Section 3(a) or
Section 22 hereof that represents Rights beneficially owned by: (i) an Acquiring
Person, an Adverse Person or any Associate or Affiliate of an Acquiring Person
or an Adverse Person, (ii) a transferee of an Acquiring Person or an Adverse
Person (or of any such Associate or Affiliate of an Acquiring Person or an
Adverse Person) who becomes a transferee after the Acquiring Person or Adverse
Person becomes such, or (iii) a transferee of an Acquiring Person or an Adverse
Person (or of any such Associate or Affiliate of an Acquiring Person or an
Adverse Person) who becomes a transferee prior to or concurrently with the
Acquiring Person or the Adverse Person becoming such and receives such Rights
pursuant to either (A) a transfer (whether or not for consideration) from the
Acquiring Person or the Adverse Person to holders of equity interests in such
Acquiring Person or Adverse Person or to any Person with whom such Acquiring
Person or Adverse Person has any continuing agreement, arrangement or
understanding regarding the transferred Rights or (B) a transfer which a
majority of the Board (with the concurrence of a majority of the Continuing
Directors) has determined is part of a plan, arrangement or understanding that
has as a primary purpose or effect avoidance of Section 7(e) hereof, and any
Rights Certificate issued pursuant to Section 6 or Section 11 hereof upon
transfer, exchange, replacement or adjustment of any other Rights Certificate
referred to in this sentence, shall contain (to the extent feasible) the
following legend:

         The Rights represented by this Rights Certificate are or were
         beneficially owned by a Person who was or became an Acquiring Person,
         Adverse Person, or an Affiliate or Associate of an Acquiring Person or
         Adverse Person (as such terms are defined in the Rights Agreement).
         Accordingly, this Rights Certificate and the Rights represented hereby
         may become null and void in the circumstances specified in Section 7(e)
         of such Agreement.

       Section 5. Countersignature and Registration.
                  ---------------------------------

              (a)    The Rights Certificates shall be executed on behalf of the
Company by its President or any Vice President, either manually or by facsimile
signature, and shall have affixed thereto the Company's seal or a facsimile
thereof which shall be attested by the Secretary or an Assistant Secretary of
the Company, either manually or by facsimile signature. The Rights Certificates
shall be manually countersigned by the Rights Agent and shall not be valid for
any 

                                      -9-
<PAGE>
 
purpose unless so countersigned. In case any officer of the Company who shall
have signed any of the Rights Certificates shall cease to be such officer of the
Company before countersignature by the Rights Agent and issuance and delivery by
the Company, such Rights Certificates, nevertheless, may be countersigned by the
Rights Agent and issued and delivered by the Company with the same force and
effect as though the person who signed such Rights Certificates had not ceased
to be such officer of the Company; and any Rights Certificates may be signed on
behalf of the Company by any person who, at the actual date of the execution of
such Rights Certificate, shall be a proper officer of the Company to sign such
Rights Certificate, although at the date of the execution of this Rights
Agreement any such person was not such an officer.

              (b)    Following the Distribution Date, the Rights Agent will keep
or cause to be kept, at its principal office or offices designated as the
appropriate place for surrender of Rights Certificates upon exercise or
transfer, books for registration and transfer of the Rights Certificates issued
hereunder. Such books shall show the names and addresses of the respective
holders of the Rights Certificates, the number of Rights evidenced on its face
by each of the Rights Certificates, the Rights Certificate number and the date
of each of the Rights Certificates.

       Section 6.  Transfer, Split Up, Combination and Exchange of Rights
                   ------------------------------------------------------
Certificates; Mutilated, Destroyed, Lost or Stolen Rights Certificates.
- -----------------------------------------------------------------------

              (a)    Subject to the provisions of Section 4(b), Section 7(e) and
Section 14 hereof, at any time after the Close of Business on the Distribution
Date, and at or prior to the Close of Business on the Expiration Date, any
Rights Certificate or Certificates may be transferred, split up, combined or
exchanged for another Rights Certificate or Certificates, entitling the
registered holder to purchase a like number of one one-hundredths of a share of
Preferred Stock (or, following a Triggering Event, Common Stock, other
securities, cash or other assets, as the case may be) as the Rights Certificate
or Certificates surrendered then entitled such holder (or former holder in the
case of a transfer) to purchase. Any registered holder desiring to transfer,
split up, combine or exchange any Rights Certificate or Certificates shall make
such request in writing delivered to the Rights Agent, and shall surrender the
Rights Certificate or Certificates to be transferred, split up, combined or
exchanged at the office of the Rights Agent designated for such purpose. Neither
the Rights Agent nor the Company shall be obligated to take any action
whatsoever with respect to the transfer of any such surrendered Rights
Certificate or Certificates until the registered holder shall have completed and
signed the certificate contained in the form of assignment set forth on the
reverse side of each such Rights Certificate and shall have provided such
additional evidence of the identity of the Beneficial Owner (or former
Beneficial Owner) or Affiliates or Associates thereof as the Company shall
reasonably request. Thereupon the Rights Agent shall, subject to Section 4(b),
Section 7(e) and Section 14 hereof, countersign and deliver to the Person
entitled thereto a Rights Certificate or Certificates, as the case may be, as so
requested. The Company may require payment of a sum sufficient to cover any tax
or governmental charge that may be imposed in connection with any transfer,
split up, combination or exchange of Rights Certificates.

              (b)    Upon receipt by the Company and the Rights Agent of
evidence reasonably satisfactory to them of the loss, theft, destruction or
mutilation of a Rights Certificate, and, in case

                                     -10-
<PAGE>
 
of loss, theft or destruction, of indemnity or security reasonably satisfactory
to them, and reimbursement to the Company and the Rights Agent of all reasonable
expenses incidental thereto, and upon surrender to the Rights Agent and
cancellation of the Rights Certificate if mutilated, the Company will execute
and deliver a new Rights Certificate of like tenor to the Rights Agent for
countersignature and delivery to the registered owner in lieu of the Rights
Certificate so lost, stolen, destroyed or mutilated.

     Section 7.  Exercise of Rights; Purchase Price; Expiration Date of
                 ------------------------------------------------------
Rights.
- ------

          (a) Subject to Section 7(e) hereof, the registered holder of any
Rights Certificate may exercise the Rights evidenced thereby (except as
otherwise provided herein including, without limitation, the restrictions set
forth in Section 9(c), Section 11(a)(iii) and Section 23(a) hereof) in whole or
in part at any time after the Distribution Date upon surrender of the Rights
Certificate, with the form of election to purchase set forth on the reverse side
thereof and the certificate contained therein completed and duly executed, to
the Rights Agent at the office of the Rights Agent designated for such purpose,
together with payment of the aggregate Purchase Price with respect to the total
number of one one-hundredths of a share of Preferred Stock (or other securities,
cash or other assets, as the case may be) as to which such surrendered Rights
are then exercisable, at or prior to the earlier of (i) the Final Expiration
Date, (ii) the time at which the Rights are redeemed as provided in Section 23
hereof, (iii) the time at which the Rights expire pursuant to Section 13(d)
hereof or (iv) the time at which such Rights are exchanged as provided in
Section 24 hereof (the earliest of (i), (ii), (iii) or (iv) being herein
referred to as the "Expiration Date").
                    ---------------   

          (b) The Purchase Price for each one one-hundredth of a share of
Preferred Stock pursuant to the exercise of a Right shall initially be the
Initial Exercise Price, and shall be subject to adjustment from time to time as
provided in Sections 11 and 13(a) hereof and shall be payable in accordance with
paragraph (c) below.

          (c) Upon receipt of a Rights Certificate representing exercisable
Rights, with the form of election to purchase set forth on the reverse side
thereof and the certificate contained therein completed and duly executed,
accompanied by payment, with respect to each Right so exercised, of the Purchase
Price per one one-hundredth of a share of Preferred Stock (or other securities,
cash or other assets, as the case may be) to be purchased as set forth below and
an amount equal to any applicable transfer tax, the Rights Agent shall, subject
to Section 20(k) hereof, promptly (i) requisition from any transfer agent of the
shares of Preferred Stock (or make available, if the Rights Agent is the
transfer agent for such shares) certificates for the total number of one one-
hundredths of a share of Preferred Stock to be purchased and the Company hereby
irrevocably authorizes its transfer agent to comply with all such requests, (ii)
requisition from the Company the amount of cash, if any, to be paid in lieu of
fractional shares in accordance with Section 14 hereof, (iii) after receipt of
such certificates, cause the same to be delivered to or upon the order of the
registered holder of such Rights Certificate, registered in such name or names
as may be designated by such holder, and (iv) after receipt thereof, deliver
such cash, if any, to or upon the order of the registered holder of such Rights
Certificate.  The payment of the Purchase Price (as such amount may be reduced
pursuant to Section 11(a)(iii) hereof) shall be made in cash 

                                    - 11 -
<PAGE>
 
or by certified check, cashier's check or bank draft payable to the order of the
Company. In the event that the Company is obligated to issue other securities
(including Common Stock) of the Company, pay cash or distribute other property
pursuant to Section 11(a) hereof, the Company will make all arrangements
necessary so that such other securities, cash or other property are available
for distribution by the Rights Agent, if and when appropriate. The Company
reserves the right to require prior to the occurrence of a Triggering Event
that, upon any exercise of Rights, such number of Rights be exercised so that
only whole shares of Common Stock would be issued.

          (d) In case the registered holder of any Rights Certificate shall
exercise less than all the Rights evidenced thereby, a new Rights Certificate
evidencing the Rights equivalent to the Rights remaining unexercised shall be
issued by the Rights Agent and delivered to, or upon the order of, the
registered holder of such Rights Certificate, registered in such name or names
as may be designated by such holder, subject to the provisions of Section 14
hereof.

          (e) Notwithstanding anything in this Agreement to the contrary, from
and after the first occurrence of an event described in Section 11(a)(ii)(A) or
(C) and from and after the Close of Business on the tenth day after the
occurrence of an event described in Section 11(a)(ii)(B) or (D), any Rights
beneficially owned by (i) an Acquiring Person, an Adverse Person or an Associate
or Affiliate of an Acquiring Person or Adverse Person, (ii) a transferee of any
such Acquiring Person or Adverse Person (or of any such Associate or Affiliate
of an Acquiring Person or an Adverse Person) who becomes a transferee after such
Acquiring Person or Adverse Person becomes such, or (iii) a transferee of any
such Acquiring Person or Adverse Person (or of any such Associate or Affiliate
of an Acquiring Person or an Adverse Person) who becomes a transferee prior to
or concurrently with such Acquiring Person or Adverse Person becoming such and
receives such Rights pursuant to either (A) a transfer (whether or not for
consideration) from such Acquiring Person or Adverse Person to holders of equity
interests in such Acquiring Person or Adverse Person or to any Person with whom
such Acquiring Person or Adverse Person has any continuing agreement,
arrangement or understanding regarding the transferred Rights or (B) a transfer
which a majority of the Board (with the concurrence of a majority of the
Continuing Directors) has determined is part of a plan, arrangement or
understanding which has as a primary purpose or effect the avoidance of this
Section 7(e), shall become null and void without any further action and no
holder of such Rights shall have any rights whatsoever with respect to such
Rights, whether under any provision of this Agreement or otherwise.  The Company
shall use all reasonable efforts to ensure that the provisions of this Section
7(e) and Section 4(b) hereof are complied with, but shall have no liability to
any holder of Rights Certificates or other Person as a result of its failure to
make any determinations with respect to an Acquiring Person or Adverse Person or
any of their Affiliates, Associates or transferees hereunder.

          (f) Notwithstanding anything in this Agreement to the contrary,
neither the Rights Agent nor the Company shall be obligated to undertake any
action with respect to a registered holder upon the occurrence of any purported
exercise as set forth in this Section 7 unless such registered holder shall have
(i) completed and signed the certificate contained in the form of election to
purchase set forth on the reverse side of the Rights Certificate surrendered for
such exercise, and (ii) provided such additional evidence of the identity of the
Beneficial Owner 

                                    - 12 -
<PAGE>
 
(or former Beneficial Owner) or Affiliates or Associates thereof as the Company
shall reasonably request.

     Section 8.  Cancellation and Destruction of Rights Certificates. All Rights
                 ---------------------------------------------------
Certificates surrendered for the purpose of exercise, transfer, split up,
combination or exchange shall, if surrendered to the Company or any of its
agents, be delivered to the Rights Agent for cancellation or in canceled form,
or, if surrendered to the Rights Agent, shall be canceled by it, and no Rights
Certificates shall be issued in lieu thereof except as expressly permitted by
any of the provisions of this Agreement. The Company shall deliver to the Rights
Agent for cancellation and retirement, and the Rights Agent shall so cancel and
retire, any other Rights Certificate purchased or acquired by the Company
otherwise than upon the exercise thereof. The Rights Agent shall deliver all
canceled Rights Certificates to the Company, or shall, at the written request of
the Company, destroy such canceled Rights Certificates, and in such case shall
deliver a certificate of destruction thereof to the Company.

     Section 9.  Reservation and Availability of Capital Stock.
                 ---------------------------------------------

          (a) The Company covenants and agrees that it will cause to be reserved
and kept available out of its authorized and unissued shares of Preferred Stock
(and, following the occurrence of a Triggering Event, out of its authorized and
unissued shares of Common Stock or other securities or out of its authorized and
issued shares held in its treasury), the number of shares of Preferred Stock
(and, following the occurrence of a Triggering Event, Common Stock or other
securities) that, as provided in this Agreement including Section 11(a)(iii)
hereof, will be sufficient to permit the exercise in full of all outstanding
Rights.

          (b) So long as the shares of Preferred Stock (and, following the
occurrence of a Triggering Event, Common Stock or other securities) issuable and
deliverable upon the exercise of the Rights may be listed on any national
securities exchange, the Nasdaq National Market or any over-the-counter market
on which the Common Stock is traded, the Company shall use its best efforts to
cause all shares reserved for such issuance to be listed on such exchange upon
official notice of issuance upon such exercise.

          (c) The Company shall use its best efforts to (i) file, as soon as
practicable following the earliest date after the first occurrence of a
Triggering Event in which the consideration to be delivered by the Company upon
exercise of the Rights has been determined in accordance with this Agreement, a
registration statement under the Act, with respect to the Common Stock or other
securities purchasable upon exercise of the Rights on an appropriate form, (ii)
cause such registration statement to become effective as soon as practicable
after such filing, and (iii) cause such registration statement to remain
effective (with a prospectus at all times meeting the requirements of the Act)
until the earlier of (A) the date as of which the Rights are no longer
exercisable for such securities, and (B) the Expiration Date.  The Company will
also take such action as may be appropriate under, or to ensure compliance with,
the securities or "blue sky" laws of the various states in connection with the
exercisability of the Rights.  The Company may temporarily suspend, for a period
of time not to exceed ninety (90) days after the date set forth in clause (i) of
the first sentence of this Section 9(c), the exercisability of the Rights in
order to 

                                    - 13 -
<PAGE>
 
prepare and file such registration statement and permit it to become effective.
In addition, if the Company shall determine that a registration statement is
required following the Distribution Date, the Company may temporarily suspend
the exercisability of the Rights until such time as a registration statement has
been declared effective. Upon any suspension of the exercisability of the Rights
referred to in this Section 9(c), the Company shall issue a public announcement
stating that the exercisability of the Rights has been temporarily suspended, as
well as a public announcement at such time as the suspension is no longer in
effect. Notwithstanding any provision of this Agreement to the contrary, the
Rights shall not be exercisable and shall be void so long as held by a holder in
any jurisdiction where the requisite qualification to the issuance to such
holder, or the exercise by such holder, of the Rights in such jurisdiction shall
not have been obtained or be obtainable, the exercise thereof shall not be
permitted under applicable law or a registration statement shall not have been
declared effective.

          (d) The Company covenants and agrees that it will take all such action
as may be necessary to ensure that all one one-hundredths of a share of
Preferred Stock (and, following the occurrence of a Triggering Event, Common
Stock or other securities) delivered upon exercise of Rights shall, at the time
of delivery of the certificates for such shares (subject to payment of the
Purchase Price), be duly and validly authorized and issued and fully paid and
nonassessable.

          (e) The Company further covenants and agrees that it will pay when due
and payable any and all federal and state transfer taxes and charges that may be
payable in respect of the issuance or delivery of the Rights Certificates and of
any certificates for a number of one one-hundredths of a share of Preferred
Stock (or Common Stock or other securities, as the case may be) upon the
exercise of Rights.  The Company shall not, however, be required to pay any
transfer tax that may be payable in respect of any transfer or delivery of
Rights Certificates to a Person other than, or the issuance or delivery of a
number of one one-hundredths of a share of Preferred Stock (or Common Stock or
other securities, as the case may be) in respect of a name other than that of,
the registered holder of the Rights Certificates evidencing Rights surrendered
for exercise or to issue or deliver any certificates for a number of one one-
hundredths of a share of Preferred Stock (or Common Stock or other securities,
as the case may be) in a name other than that of the registered holder upon the
exercise of any Rights until such tax shall have been paid (any such tax being
payable by the holder of such Rights Certificates at the time of surrender) or
until it has been established to the Company's satisfaction that no such tax is
due.

     Section 10.  Preferred Stock Record Date. Each Person in whose name any
                  ----------------------------
certificate for a number of one one-hundredths of a share of Preferred Stock (or
Common Stock or other securities, as the case may be) is issued upon the
exercise of Rights shall for all purposes be deemed to have become the holder of
record of such Preferred Stock (or Common Stock or other securities, as the case
may be) represented thereby on, and such certificate shall be dated, the date
upon which the Rights Certificate evidencing such Rights was duly surrendered
and payment of the Purchase Price (and all applicable transfer taxes) was made;
provided, however, that if the date of such surrender and payment is a date upon
- --------  -------             
which the Preferred Stock (or Common Stock or other securities, as the case may
be) transfer books of the Company are closed, such Person shall be deemed to
have become the record holder of such shares on, and such certificate shall be
dated, the next succeeding Business Day on which the Preferred Stock (or other
securities, as the case 

                                    - 14 -
<PAGE>
 
may be) transfer books of the Company are open. Prior to the exercise of the
Rights evidenced thereby, the holder of a Rights Certificate shall not be
entitled to any rights of a stockholder of the Company with respect to shares
for which the Rights shall be exercisable, including, without limitation, the
right to vote, to receive dividends or other distributions or to exercise any
preemptive rights, and shall not be entitled to receive any notice of any
proceedings of the Company, except as provided herein.

     Section 11.  Adjustment of Purchase Price, Number and Kind of Shares or
                  ----------------------------------------------------------
Number of Rights. The Purchase Price, the number and kind of shares covered
- -----------------
by each Right and the number of Rights outstanding are subject to adjustment
from time to time as provided in this Section 11.

          (a)(i) In the event the Company shall at any time after the date of
this Agreement (A) declare a dividend on the Preferred Stock payable in shares
of Preferred Stock, (B) subdivide the outstanding Preferred Stock, (C) combine
the outstanding Preferred Stock into a smaller number of shares, or (D) issue
any shares of its capital stock in a reclassification of the Preferred Stock
(including any such reclassification in connection with a consolidation or
merger in which the Company is the continuing or surviving corporation), except
as otherwise provided in this Section 11(a) and Section 7(e) hereof, the
Purchase Price in effect at the time of the record date for such dividend or of
the effective date of such subdivision, combination or reclassification, and the
number and kind of shares of Preferred Stock or capital stock, as the case may
be, issuable on such date, shall be proportionately adjusted so that if a holder
of Rights after such time were to exercise that number of Rights (or fraction
thereof) which would result in the aggregate amount of the Purchase Price
payable upon such exercise (at the Purchase Price then in effect) being equal to
the amount of the Purchase Price payable prior to such time upon exercise of a
Right, he would be entitled to receive the aggregate number and kind of shares
of Preferred Stock or other capital stock, as the case may be, which, if a Right
had been exercised immediately prior to such time and at a time when the
Preferred Stock transfer books (or other capital stock transfer books, as the
case may be) of the Company were open, he would have owned upon such exercise
and been entitled to receive by virtue of such dividend, subdivision,
combination or reclassification.  If an event occurs that would require an
adjustment under both this Section 11(a)(i) and Section 11(a)(ii) hereof, the
adjustment provided for in this Section 11(a)(i) shall be in addition to, and
shall be made prior to, any adjustment required pursuant to Section 11(a)(ii)
hereof.

     (ii) In the event:

          (A) any Acquiring Person or any Associate or Affiliate of any
Acquiring Person, at any time after the date of this Agreement, directly or
indirectly, (1) shall merge into the Company or otherwise combine with the
Company and the Company shall be the continuing or surviving corporation of such
merger or combination and the Common Stock of the Company shall remain
outstanding and unchanged, (2) shall merge or otherwise combine with any
Subsidiary of the Company, (3) shall, in one transaction or a series of
transactions, transfer any assets to the Company or to any of its Subsidiaries
in exchange (in whole or in part) for shares of Common Stock, for shares of
other equity or voting securities of the Company or any Subsidiary of the
Company, or for securities exercisable for or convertible into shares of equity
or voting securities of the Company or any Subsidiary of the Company (Common
Stock or otherwise) or 

                                    - 15 -
<PAGE>
 
otherwise obtain from the Company, with or without consideration, any additional
shares of equity or voting securities of the Company or securities exercisable
for or convertible into shares of such equity securities of the Company (other
than pursuant to a pro rata distribution to all holders of Common Stock or upon
the exercise of a convertible security of the Company or any Subsidiary of the
Company in accordance with its terms), (4) shall sell, purchase, lease,
exchange, mortgage, pledge, transfer or otherwise acquire or dispose of, in one
transaction or a series of transactions, to, from or with (as the case may be)
the Company or any of its Subsidiaries, assets on terms and conditions less
favorable to the Company than the Company would be able to obtain in arm's
length negotiations with an unaffiliated third party, other than pursuant to a
transaction set forth in Section 13(a) hereof, (5) shall sell, purchase, lease,
exchange, mortgage, pledge, transfer or otherwise acquire or dispose of in one
transaction or a series of transactions, to, from or with (as the case may be)
the Company or any of its Subsidiaries assets having an aggregate fair market
value of more than $1,000,000, other than pursuant to a transaction set forth in
Section 13(a) hereof and other than pursuant to a transaction or series of
transactions that have been approved by a majority of the Continuing Directors,
(6) shall receive any compensation from the Company or any of the Company's
Subsidiaries other than compensation for full-time employment as a regular
employee at rates in accordance with the Company's (or its Subsidiaries') past
practices, or (7) shall receive the benefit, directly or indirectly (except
proportionately as a stockholder and except if resulting from a requirement of
law or governmental regulation), of any loans, advances, guarantees, pledges or
other financial assistance or any tax credits or other tax advantages provided
by the Company or any of its Subsidiaries, or

          (B) any Person (other than the Company, any Subsidiary of the Company,
any employee benefit plan of the Company or of any Subsidiary of the Company, or
any Person or entity organized, appointed or established by the Company for or
pursuant to the terms of any such plan), alone or together with any Affiliates
and Associates of such Person, shall, at any time after the Rights Dividend
Declaration Date, become the Beneficial Owner of 20% or more of the shares of
Common Stock then outstanding, unless (1) the event causing the 20% threshold to
be crossed is a transaction set forth in Section 13(a) hereof or (2) is an
acquisition of shares of Common Stock pursuant to a tender offer or an exchange
offer for all outstanding shares of Common Stock at a price and on terms
determined by a majority of the Independent Directors, after receiving advice
from one or more investment banking firms, to be (a) at a price that is fair to
stockholders (taking into account all factors which such members of the Board
deem relevant including, without limitation, prices which could reasonably be
achieved if the Company or its assets were sold on an orderly basis designed to
realize maximum value) and (b) otherwise in the best interest of the Company and
its stockholders, or

          (C) during such time as there is an Acquiring Person, there shall be
any reclassification of securities (including any reverse stock split), or
recapitalization of the Company, or any merger or consolidation of the Company
with any of its Subsidiaries or any other transaction or series of transactions
involving the Company or any of its Subsidiaries (whether or not with or into or
otherwise involving an Acquiring Person), other than a transaction or
transactions to which the provisions of Section 13(a) hereof apply (whether or
not with or into or otherwise involving an Acquiring Person), which has the
effect, directly or indirectly, of increasing by more than 1% the proportionate
share of the outstanding shares of any class of 

                                    - 16 -
<PAGE>
 
equity securities of the Company or any of its Subsidiaries which is directly or
indirectly beneficially owned by any Acquiring Person or any Associate or
Affiliate of any Acquiring Person, or

          (D) a majority of the Continuing Directors shall declare any Person to
be an Adverse Person, upon a determination that such Person, alone or together
with its Affiliates and Associates, has, at any time after the Rights Dividend
Declaration Date, become the Beneficial Owner of an amount of Common Stock which
a majority of Continuing Directors determine to be substantial (which amount
shall in no event be less than 10% of the shares of Common Stock then
outstanding) and a majority of the Continuing Directors determines (with the
concurrence of a majority of the Independent Directors), after reasonable
inquiry and investigation, which may include a review of the public record
regarding such Person and any information such directors may request from such
Person and consultation with such persons as such directors shall deem
appropriate, that (1) such Beneficial Ownership by such Person is intended to
cause the Company to repurchase the Common Stock beneficially owned by such
Person or to cause pressure on the Company to take action or enter into a
transaction or series of transactions intended to provide such Person with
short-term financial gain under circumstances where such directors determine
that the best long-term interests of the Company and its stockholders would not
be served by taking such action or entering into such transactions or series of
transactions at that time or (2) such Beneficial Ownership is causing or is
reasonably likely to cause a material adverse impact (including, but not limited
to, impairment of relationships with customers, impairment of the Company's
ability to maintain its competitive position or impairment of the Company's
business reputation) on the business or prospects of the Company,

then, immediately upon the occurrence of any event described in Section
11(a)(ii)(A) or (C) hereof, and upon the Close of Business ten (10) days after
the occurrence of any event described in Section 11(a)(ii)(B) or (D) hereof,
proper provision shall be made so that each holder of a Right (except as
provided below and in Section 7(e) hereof) shall thereafter have the right to
receive, upon exercise thereof at the then current Purchase Price in accordance
with the terms of this Agreement, in lieu of a number of one one-hundredths of a
share of Preferred Stock, such number of shares of Common Stock of the Company
as shall equal the result obtained by (x) multiplying the then current Purchase
Price by the then number of one one-hundredths of a share of Preferred Stock for
which a Right was or would have been exercisable immediately prior to the first
occurrence of a Section 11(a)(ii) Event, whether or not such Right was then
exercisable, and (y) dividing that product (which, following such first
occurrence, shall thereafter be referred to as the "Purchase Price" for each
                                                    --------------          
Right and for all purposes of this Agreement) by 50% of the Current Market Price
per share of Common Stock (determined pursuant to Section 11(d) hereof) on the
date of such first occurrence (such number of shares being referred to herein as
the "Adjustment Shares").
     -----------------   

     (iii)  In the event that the number of shares of Common Stock which are
authorized by the Company's  Certificate of Incorporation, as amended as of the
date of the most recent occurrence of a Section 11(a)(ii) Event, but not
outstanding or reserved for issuance for purposes other than upon exercise of
the Rights are not sufficient to permit the exercise in full of the Rights in
accordance with the foregoing subparagraph (ii) of this Section 11(a), the
Company 

                                    - 17 -
<PAGE>
 
shall (A) determine the value of the Adjustment Shares issuable upon the
exercise of a Right (the "Current Value"), and (B) with respect to each Right
                          -------------                                      
(subject to Section 7(e) hereof), make adequate provision to substitute, upon
the exercise of a Right and payment of the applicable Purchase Price, (1) cash,
(2) a reduction in the Purchase Price, (3) Common Stock or other equity
securities of the Company (including, without limitation, shares, or units of
shares, of preferred stock which the Board has deemed to have the same value as
shares of Common Stock (such shares of preferred stock being referred to herein
as "Common Stock Equivalents")), (4) debt securities of the Company, (5) other
    ------------------------                                                  
assets, or (6) any combination of the foregoing, having an aggregate value equal
to the Current Value, as adjusted (less the amount of any reduction in the
Purchase Price), where such aggregate value has been determined by the Board
based upon the advice of a nationally recognized investment banking firm
selected by the Board; provided, however, that if the Company shall not have
                       --------  -------                                    
made adequate provision to deliver value pursuant to clause (B) above within
thirty (30) days following the later of (x) the first occurrence of a Section
11(a)(ii) Event and (y) the first date on which the Company's right of
redemption pursuant to Section 23(a) expires (the later of (x) and (y) being
referred to herein as the "Section 11(a)(ii) Trigger Date"), then the Company
                           ------------------------------                    
shall be obligated to deliver, upon the surrender for exercise of a Right and
without requiring payment of the Purchase Price, shares of Common Stock (to the
extent available) and then, if necessary, cash, which shares or cash have an
aggregate value equal to the Spread.  For purposes of the preceding sentence,
the term "Spread" shall mean the excess of (i) the Current Value over (ii) the
          ------                                                              
Purchase Price.  If the number of shares of Common Stock that are authorized by
the Company's  Certificate of Incorporation, as amended as of the date of the
most recent occurrence of a Section 11(a)(ii) Event, but not outstanding or
reserved for issuance for purposes other than upon exercise of the Rights are
not sufficient to permit the exercise in full of any Rights and the Board
determines in good faith that it is likely that sufficient additional shares of
Common Stock could be authorized for issuance upon exercise in full of the
Rights, the thirty (30) day period set forth above may be extended to the extent
necessary, but not more than ninety (90) days after the Section 11(a)(ii)
Trigger Date, in order that the Company may seek stockholder approval for the
authorization of such additional shares (such thirty (30) day period, as it may
be extended, shall be referred to as the "Substitution Period").  To the extent
                                          -------------------                  
that the Company determines that some action need be taken pursuant to the
preceding provisions of this Section 11(a)(iii), the Company (x) shall provide,
subject to Section 7(e) hereof, that such action shall apply uniformly to all
outstanding Rights, and (y) may suspend the exercisability of the Rights until
the expiration of the Substitution Period in order to seek any authorization of
additional shares or to decide the appropriate form of distribution to be made
pursuant to such provisions and to determine the value thereof.  In the event of
any such suspension, the Company shall issue a public announcement stating that
the exercisability of the Rights has been temporarily suspended, as well as a
public announcement at such time as the suspension is no longer in effect.  For
purposes of this Section 11(a)(iii), the value of each Adjustment Share shall be
the Current Market Price per share of the Common Stock (as determined pursuant
to Section 11(d) hereof) on the Section 11(a)(ii) Trigger Date and the per share
or per unit value of any Common Stock Equivalent shall be deemed to equal the
Current Market Price per share of the Common Stock on such date.

          (b) In case the Company shall fix a record date for the issuance of
rights (other than the Rights), options or warrants to all holders of Preferred
Stock entitling them to subscribe 

                                    - 18 -
<PAGE>
 
for or purchase (for a period expiring within forty-five (45) calendar days
after such record date) Preferred Stock, shares having the same rights,
privileges and preferences as the shares of Preferred Stock ("Equivalent
                                                              ----------  
Preferred Stock") or securities convertible into Preferred Stock or Equivalent
- ---------------
Preferred Stock at a price per share of Preferred Stock or per share of
Equivalent Preferred Stock (or having a conversion price per share, if a
security convertible into Preferred Stock or Equivalent Preferred Stock) less
than the Current Market Price per share of Preferred Stock (as determined
pursuant to Section 11(d) hereof) on such record date, the Purchase Price to be
in effect after such record date shall be determined by multiplying the Purchase
Price in effect immediately prior to such record date by a fraction, the
numerator of which shall be the number of shares of Preferred Stock outstanding
on such record date, plus the number of shares of Preferred Stock which the
aggregate offering price of the total number of shares of Preferred Stock or
Equivalent Preferred Stock (or the aggregate initial conversion price of the
convertible securities so to be offered) would purchase at such Current Market
Price, and the denominator of which shall be the number of shares of Preferred
Stock outstanding on such record date, plus the number of additional shares of
Preferred Stock or Equivalent Preferred Stock to be offered for subscription or
purchase (or into which the convertible securities so to be offered are
initially convertible). In case such subscription price may be paid by delivery
of consideration part or all of which may be in a form other than cash, the
value of such noncash consideration shall be as determined in good faith by the
Board, whose determination shall be described in a statement filed with the
Rights Agent and shall be binding on the Rights Agent and the holders of the
Rights. Shares of Preferred Stock owned by or held for the account of the
Company shall not be deemed outstanding for the purpose of any such computation.
Such adjustment shall be made successively whenever such a record date is fixed,
and in the event that such rights, options or warrants are not so issued, the
Purchase Price shall be adjusted to be the Purchase Price which would then be in
effect if such record date had not been fixed.

          (c) In case the Company shall fix a record date for a distribution to
all holders of Preferred Stock (including any such distribution made in
connection with a consolidation or merger in which the Company is the continuing
or surviving corporation) of evidences of indebtedness, cash (other than a
regular quarterly or other periodic cash dividend out of the earnings or
retained earnings of the Company), assets (other than a dividend payable in
Preferred Stock, but including any dividend payable in stock other than
Preferred Stock) or subscription rights or warrants (excluding those referred to
in Section 11(b) hereof), the Purchase Price to be in effect after such record
date shall be determined by multiplying the Purchase Price in effect immediately
prior to such record date by a fraction, the numerator of which shall be the
Current Market Price per share of Preferred Stock (as determined pursuant to
Section 11(d) hereof) on such record date, less the fair market value (as
determined in good faith by the Board whose determination shall be described in
a statement filed with the Rights Agent and shall be binding on the Rights
Agent) of the portion of the cash, assets or evidences of indebtedness so to be
distributed or of such subscription rights or warrants applicable to a share of
Preferred Stock and the denominator of which shall be such Current Market Price
per share of Preferred Stock (as determined pursuant to Section 11(d) hereof).
Such adjustments shall be made successively whenever such a record date is
fixed, and in the event that such distribution is not so made, the Purchase
Price shall be adjusted to be the Purchase Price which would have been in effect
if such record date had not been fixed.

                                    - 19 -
<PAGE>
 
          (d) (i) For the purpose of any computation hereunder, other than
computations made pursuant to Section 11(a)(iii) hereof, the Current Market
Price per share of Common Stock on any date shall be deemed to be the average of
the daily closing prices per share of such Common Stock for the thirty (30)
consecutive Trading Days immediately prior to such date, and for the purposes of
computations made pursuant to Section 11(a)(iii) hereof, the Current Market
Price per share of Common Stock on any date shall be deemed to be the average of
the daily closing prices per share of such Common Stock for the ten (10)
consecutive Trading Days immediately following such date; provided, however,
                                                          --------  ------- 
that in the event that the Current Market Price per share of the Common Stock is
determined during a period following the announcement by the issuer of such
Common Stock of (A) any dividend or distribution on such Common Stock payable in
shares of such Common Stock or securities convertible into shares of such Common
Stock (other than Rights), or (B) any subdivision, combination or
reclassification of such Common Stock, and prior to the expiration of the
requisite thirty (30) Trading Day or ten (10) Trading Day period, as set forth
above, after the ex-dividend date for such dividend or distribution, or the
record date for such subdivision, combination or reclassification, then, and in
each such case, the Current Market Price shall be properly adjusted to take into
account ex-dividend trading.  The closing price for each day shall be the last
sale price, regular way, or, in case no such sale takes place on such day, the
average of the closing bid and asked prices, regular way, in either case as
reported in the principal consolidated transaction reporting system with respect
to securities listed on the principal national securities exchange on which the
shares of Common Stock are listed or admitted to trading or, if the shares of
Common Stock are not listed or admitted to trading on any national securities
exchange, the last quoted price or, if not so quoted, the average of the high
bid and low asked prices on the Nasdaq National Market or in the over-the-
counter market, as reported by Nasdaq or such other system then in use, or, if
on any such date the shares of Common Stock are not quoted by any such
organization, the average of the closing bid and asked prices as furnished by a
professional market maker making a market in the Common Stock selected by the
Board.  If on any such date no market maker is making a market in the Common
Stock, the fair value of such shares on such date as determined in good faith by
the Board shall be used.  The term "Trading Day" shall mean a day on which the
                                    -----------                               
principal national securities exchange on which the shares of Common Stock are
listed or admitted to trading is open for the transaction of business or, if the
shares of Common Stock are not listed or admitted to trading on any national
securities exchange, a Business Day.  If the Common Stock is not publicly held
or not so listed or traded, Current Market Price per share shall mean the fair
value per share as determined in good faith by the Board  whose determination
shall be described in a statement filed with the Rights Agent and shall be
conclusive for all purposes.

              (ii) For the purpose of any computation hereunder, the Current
Market Price per share of Preferred Stock shall be determined in the same manner
as set forth above for the Common Stock in clause (i) of this Section 11(d)
(other than the last sentence thereof). If the Current Market Price per share of
Preferred Stock cannot be determined in the manner provided above or if the
Preferred Stock is not publicly held or listed or traded in a manner described
in clause (i) of this Section 11(d), the Current Market Price per share of
Preferred Stock shall be conclusively deemed to be an amount equal to 100 (as
such number may be appropriately adjusted for such events as stock splits, stock
dividends and recapitalizations with respect to the Common

                                    - 20 -
<PAGE>
 
Stock occurring after the date of this Agreement) multiplied by the Current
Market Price per share of the Common Stock. If neither the Common Stock nor the
Preferred Stock is publicly held or so listed or traded, Current Market Price
per share of the Preferred Stock shall mean the fair value per share as
determined in good faith by the Board, whose determination shall be described in
a statement filed with the Rights Agent and shall be conclusive for all
purposes. For all purposes of this Agreement, the Current Market Price of one
one-hundredth of a share of Preferred Stock shall be equal to the Current Market
Price of one share of Preferred Stock divided by 100.

              (iii) For the purpose of any computation hereunder, the value of
any securities or assets other than Common Stock or Preferred Stock shall be the
fair value as determined in good faith by the Board, or, if at the time of such
determination there is an Acquiring Person, by a majority of the Continuing
Directors then in office, or, if there are no Continuing Directors, by a
nationally recognized investment banking firm selected by the Board, which
determination shall be described in a statement filed with the Rights Agent and
shall be conclusive for all purposes.

          (e) Anything herein to the contrary notwithstanding, no adjustment in
the Purchase Price shall be required unless such adjustment would require an
increase or decrease of at least one percent (1%) in the Purchase Price;
                                                                        
provided, however, that any adjustments which by reason of this Section 11(e)
- --------  -------                                                            
are not required to be made shall be carried forward and taken into account in
any subsequent adjustment.  All calculations under this Section 11 shall be made
to the nearest cent or to the nearest ten-thousandth of a share of Common Stock
or other share or one-millionth of a share of Preferred Stock, as the case may
be.  Notwithstanding the first sentence of this Section 11(e), any adjustment
required by this Section 11 shall be made no later than the earlier of (i) three
(3) years from the date of the transaction which mandates such adjustment, or
(ii) the Expiration Date.

          (f) If as a result of an adjustment made pursuant to Section 11(a)(ii)
or Section 13(a) hereof, the holder of any Right thereafter exercised shall
become entitled to receive any shares of capital stock other than Preferred
Stock, thereafter the number of such other shares so receivable upon exercise of
any Right and the Purchase Price thereof shall be subject to adjustment from
time to time in a manner and on terms as nearly equivalent as practicable to the
provisions with respect to the Preferred Stock contained in Sections 11(a), (b),
(c), (e), (g), (h), (i), (j), (k) and (m) hereof, and the provisions of Sections
7, 9, 10, 13 and 14 hereof with respect to the Preferred Stock shall apply on
like terms to any such other shares.

          (g) All Rights originally issued by the Company subsequent to any
adjustment made to the Purchase Price hereunder shall evidence the right to
purchase, at the adjusted Purchase Price, the number of one one-hundredths of a
share of Preferred Stock purchasable from time to time hereunder upon exercise
of the Rights, all subject to further adjustment as provided herein.

          (h) Unless the Company shall have exercised its election as provided
in Section 11(i) hereof, upon each adjustment of the Purchase Price as a result
of the calculations made in Sections 11(b) and (c) hereof, each Right
outstanding immediately prior to the making of such 

                                    - 21 -
<PAGE>
 
adjustment shall thereafter evidence the right to purchase, at the adjusted
Purchase Price, that number of one one-hundredths of a share of Preferred Stock
obtained by (i) multiplying (x) the number of one one-hundredths of a share
covered by a Right immediately prior to this adjustment, by (y) the Purchase
Price in effect immediately prior to such adjustment of the Purchase Price, and
(ii) dividing the product so obtained by the Purchase Price in effect
immediately after such adjustment of the Purchase Price.

          (i) The Company may elect on or after the date of any adjustment of
the Purchase Price to adjust the number of Rights, in lieu of any adjustment in
the number of shares of Preferred Stock purchasable upon the exercise of a
Right.  Each of the Rights outstanding after the adjustment in the number of
Rights shall be exercisable for the number of one one-hundredths of a share of
Preferred Stock for which a Right was exercisable immediately prior to such
adjustment.  Each Right held of record prior to such adjustment of the number of
Rights shall become that number of Rights (calculated to the nearest one-ten-
thousandth) obtained by dividing the Purchase Price in effect immediately prior
to adjustment of the Purchase Price by the Purchase Price in effect immediately
after adjustment of the Purchase Price.  The Company shall make a public
announcement of its election to adjust the number of Rights, indicating the
record date for the adjustment, and, if known at the time, the amount of the
adjustment to be made.  This record date may be the date on which the Purchase
Price is adjusted or any day thereafter, but, if the Rights Certificates have
been issued, shall be at least ten (10) days later than the date of the public
announcement.  If Rights Certificates have been issued, upon each adjustment of
the number of Rights pursuant to this Section 11(i), the Company shall, as
promptly as practicable, cause to be distributed to holders of record of Rights
Certificates on such record date Rights Certificates evidencing, subject to
Section 14 hereof, the additional Rights to which such holders shall be entitled
as a result of such adjustment, or, at the option of the Company, shall cause to
be distributed to such holders of record in substitution and replacement for the
Rights Certificates held by such holders prior to the date of adjustment, and
upon surrender thereof, if required by the Company, new Rights Certificates
evidencing all the Rights to which such holders shall be entitled after such
adjustment.  Rights Certificates so to be distributed shall be issued, executed
and countersigned in the manner provided for herein (and may bear, at the option
of the Company, the adjusted Purchase Price) and shall be registered in the
names of the holders of record of Rights Certificates on the record date
specified in the public announcement.

          (j) Irrespective of any adjustment or change in the Purchase Price or
the number of one one-hundredths of a share of Preferred Stock issuable upon the
exercise of the Rights, the Rights Certificates theretofore and thereafter
issued may continue to express the Purchase Price per share and the number of
shares which were expressed in the initial Rights Certificates issued hereunder.

          (k) Before taking any action that would cause an adjustment reducing
the Purchase Price below the then par value of the shares of Common Stock
issuable upon exercise of the Rights, the Company shall take any corporate
action which may, in the opinion of its counsel, be necessary in order that the
Company may validly and legally issue fully paid and nonassessable such number
of one one-hundredths of a share of Preferred Stock at such adjusted Purchase
Price.

                                    - 22 -
<PAGE>
 
          (l) In any case in which this Section 11 shall require that an
adjustment in the Purchase Price be made effective as of a record date for a
specified event, the Company may elect to defer until the occurrence of such
event the issuance to the holder of any Right exercised after such record date
the number of one one-hundredths of a share of Preferred Stock and other capital
stock or securities of the Company, if any, issuable upon such exercise over and
above the number of one one-hundredths of a  share of Preferred Stock and other
capital stock or securities of the Company, if any, issuable upon such exercise
on the basis of the Purchase Price in effect prior to such adjustment; provided,
                                                                       -------- 
however, that the Company shall deliver to such holder a due bill or other
- -------                                                                   
appropriate instrument evidencing such holder's right to receive such additional
shares or securities upon the occurrence of the event requiring such adjustment.

          (m) Anything in this Section 11 to the contrary notwithstanding, the
Company shall be entitled to make such reductions in the Purchase Price, in
addition to those adjustments expressly required by this Section 11, as and to
the extent that in their good faith judgment the Board shall determine to be
advisable in order that any (i) consolidation or subdivision of the Preferred
Stock, (ii) issuance wholly for cash of any shares of Preferred Stock at less
than the Current Market Price, (iii) issuance wholly for cash of shares of
Preferred Stock or securities which by their terms are convertible into or
exchangeable for shares of Preferred Stock, (iv) stock dividends, or (v)
issuance of rights, options or warrants referred to in this Section 11,
hereafter made by the Company to holders of its Preferred Stock shall not be
taxable to such stockholders.

          (n) The Company covenants and agrees that it shall not, at any time
after the Distribution Date, (i) consolidate with any other Person (other than a
Subsidiary of the Company in a transaction that complies with Section 11(o)
hereof), (ii) merge with or into any other Person (other than a Subsidiary of
the Company in a transaction which complies with Section 11(o) hereof), or (iii)
sell or transfer (or permit any Subsidiary to sell or transfer), in one
transaction, or a series of related transactions, assets or earning power
aggregating more than 50% of the assets or earning power of the Company and its
Subsidiaries (taken as a whole) to any other Person or Persons (other than the
Company or any of its Subsidiaries in one or more transactions each of which
complies with Section 11(o) hereof), if (x) at the time of or immediately after
such consolidation, merger or sale there are any rights, warrants or other
instruments or securities outstanding or agreements in effect that would
substantially diminish or otherwise eliminate the benefits intended to be
afforded by the Rights or (y) prior to, simultaneously with or immediately after
such consolidation, merger or sale, the stockholders of the Person who
constitutes, or would constitute, the "Principal Party" for purposes of Section
                                       ---------------                         
13(a) hereof shall have received a distribution of Rights previously owned by
such Person or any of its Affiliates and Associates.

          (o) The Company covenants and agrees that, after the Distribution
Date, it will not, except as permitted by Section 23 or Section 27 hereof, take
(or permit any Subsidiary to take) any action if at the time such action is
taken it is reasonably foreseeable that such action will diminish substantially
or otherwise eliminate the benefits intended to be afforded by the Rights.

          (p) Anything in this Agreement to the contrary notwithstanding, in the
event that the Company shall at any time after the Rights Dividend Declaration
Date and prior to the Distribution Date (i) declare a dividend on the
outstanding shares of Common Stock payable in 

                                    - 23 -
<PAGE>
 
shares of Common Stock other than the Stock Split, (ii) subdivide the
outstanding shares of Common Stock, or (iii) combine the outstanding shares of
Common Stock into a smaller number of shares, the number of Rights associated
with each share of Common Stock then outstanding, or issued or delivered
thereafter but prior to the Distribution Date, shall be proportionately adjusted
so that the number of Rights thereafter associated with each share of Common
Stock following any such event shall equal the result obtained by multiplying
the number of Rights associated with each share of Common Stock immediately
prior to such event by a fraction the numerator of which shall be the total
number of shares of Common Stock outstanding immediately prior to the occurrence
of the event and the denominator of which shall be the total number of shares of
Common Stock outstanding immediately following the occurrence of such event.

          (q) The failure by the Continuing Directors to declare (or the
Independent Directors to concur therewith) a Person to be an Adverse Person
following such Person becoming the Beneficial Owner of 10% or more of the
outstanding Common Stock shall not imply that such Person is not an Adverse
Person or limit such directors' right at any time in the future to declare such
Person to be an Adverse Person.

     Section 12.  Certificate of Adjusted Purchase Price or Number of Shares.
                  -----------------------------------------------------------
Whenever an adjustment is made as provided in Section 11 and Section 13 hereof,
the Company shall (a) promptly prepare a certificate setting forth such
adjustment and a brief statement of the facts accounting for such adjustment,
(b) promptly file with the Rights Agent, and with each transfer agent for the
Preferred Stock and the Common Stock, a copy of such certificate, and (c) mail a
brief summary thereof to each holder of a Rights Certificate (or, if prior to
the Distribution Date, to each holder of a certificate representing shares of
Common Stock) in accordance with Section 26 hereof. The Rights Agent shall be
fully protected in relying on any such certificate and on any adjustment therein
contained.

     Section 13.  Consolidation, Merger or Sale or Transfer of  Assets or
                  -------------------------------------------------------
Earning Power.
- --------------

          (a) In the event that, following the Stock Acquisition Date, directly
or indirectly, (x) the Company shall consolidate with, or merge with and into,
any other Person (other than a Subsidiary of the Company in a transaction that
complies with Section 11(o) hereof), and the Company shall not be the continuing
or surviving corporation of such consolidation or merger, (y) any Person (other
than a Subsidiary of the Company in a transaction that complies with Section
11(o) hereof) shall consolidate with, or merge with or into, the Company, and
the Company shall be the continuing or surviving corporation of such
consolidation or merger and, in connection with such consolidation or merger,
all or part of the outstanding shares of Common Stock shall be changed into or
exchanged for stock or other securities of any other Person or cash or any other
property, or (z) the Company shall sell or otherwise transfer (or one or more of
its Subsidiaries shall sell or otherwise transfer), in one transaction or a
series of related transactions, assets or earning power aggregating more than
50% of the assets or earning power of the Company and its Subsidiaries (taken as
a whole) to any Person or Persons (other than the Company or any Subsidiary of
the Company in one or more transactions each of which complies with Section
11(o) hereof), then, and in each such case and except as contemplated in Section
13(d) hereof, proper provision shall be made so that:  (i) each holder of a
Right, except as 

                                    - 24 -
<PAGE>
 
provided in Section 7(e) hereof, shall thereafter have the right to receive,
upon the exercise thereof at the then current Purchase Price in accordance with
the terms of this Agreement, such number of validly authorized and issued, fully
paid, nonassessable and freely tradeable shares of Common Stock of the Principal
Party (as such term is hereinafter defined), not subject to any liens,
encumbrances, rights of first refusal or other adverse claims, as shall be equal
to the result obtained by (1) multiplying the then current Purchase Price by the
number of one one-hundredths of a share of Preferred Stock for which a Right was
exercisable immediately prior to the first occurrence of a Section 13 Event (or,
if a Section 11(a)(ii) Event has occurred prior to the first occurrence of a
Section 13 Event, multiplying the number of such one one-hundredths of a share
for which a Right was exercisable immediately prior to the first occurrence of a
Section 11(a)(ii) Event by the Purchase Price in effect immediately prior to
such first occurrence), and dividing that product (which, following the first
occurrence of a Section 13 Event, shall be referred to as the "Purchase Price"
                                                               -------------- 
for each Right and for all purposes of this Agreement) by (2) 50% of the Current
Market Price (determined pursuant to Section 11(d)(i) hereof) per share of the
Common Stock of such Principal Party on the date of consummation of such Section
13 Event; (ii) such Principal Party shall thereafter be liable for, and shall
assume, by virtue of such Section 13 Event, all the obligations and duties of
the Company pursuant to this Agreement; (iii) the term "Company" shall
                                                        -------  
thereafter be deemed to refer to such Principal Party, it being specifically
intended that the provisions of Section 11 hereof shall apply only to such
Principal Party following the first occurrence of a Section 13 Event; (iv) such
Principal Party shall take such steps (including, but not limited to, the
reservation of a sufficient number of shares of its Common Stock) in connection
with the consummation of any such transaction as may be necessary to assure that
the provisions hereof shall thereafter be applicable, as nearly as reasonably
may be, in relation to its shares of Common Stock thereafter deliverable upon
the exercise of the Rights; and (v) the provisions of Section 11(a)(ii) hereof
shall be of no effect following the first occurrence of any Section 13 Event.

          (b)  "Principal Party" shall mean
                ---------------            

                          (i)   in the case of any transaction described in
                clause (x) or (y) of the first sentence of Section 13(a) hereof,
                the Person that is the issuer of any securities into which
                shares of Common Stock of the Company are converted in such
                merger or consolidation, and if no securities are so issued, the
                Person that is the other party to such merger or consolidation;
                and

                          (ii)  in the case of any transaction described in
                clause (z) of the first sentence of Section 13(a) hereof, the
                Person that is the party receiving the greatest portion of the
                assets or earning power transferred pursuant to such transaction
                or transactions;

provided, however, that in any such case, (1) if the Common Stock of such Person
- --------  -------                                                               
is not at such time and has not been continuously over the preceding twelve (12)
month period registered under Section 12 of the Exchange Act, and such Person is
a direct or indirect Subsidiary of another Person the Common Stock of which is
and has been so registered, "Principal Party" shall refer to such other Person;
and (2) in case such Person is a Subsidiary, directly or indirectly, of more
than one Person, the Common Stocks of two or more of which are and have been so
registered, "Principal Party" shall refer to 

                                    - 25 -
<PAGE>
 
such other Person; and (2) in case such Person is a Subsidiary, directly or
indirectly, of more than one Person, the Common Stocks of two or more of which
are and have been so registered, "Principal Party" shall refer to whichever of
such Persons is the issuer of the Common Stock having the greatest aggregate
market value.

          (c) The Company shall not consummate any such consolidation, merger,
sale or transfer unless the Principal Party shall have a sufficient number of
authorized shares of its Common Stock which have not been issued or reserved for
issuance to permit the exercise in full of the Rights in accordance with this
Section 13 and unless prior thereto the Company and such Principal Party shall
have executed and delivered to the Rights Agent a supplemental agreement
providing for the terms set forth in paragraphs (a) and (b) of this Section 13
and further providing that, as soon as practicable after the date of any Section
13 Event, the Principal Party will:

              (i)   prepare and file a registration statement under the Act,
with respect to the Rights and the securities purchasable upon exercise of the
Rights on an appropriate form, and will use its best efforts to cause such
registration statement to (A) become effective as soon as practicable after such
filing and (B) remain effective (with a prospectus at all times meeting the
requirements of the Act) until the Expiration Date; and

              (ii)  deliver to holders of the Rights historical financial
statements for the Principal Party and each of its Affiliates that comply in all
respects with the requirements for registration on Form 10 under the Exchange
Act.

The provisions of this Section 13 shall similarly apply to successive mergers or
consolidations or sales or other transfers.  In the event that a Section 13
Event shall occur at any time after the occurrence of a Section 11(a)(ii) Event,
the Rights which have not theretofore been exercised shall thereafter become
exercisable in the manner described in Section 13(a) hereof.

          (d) Notwithstanding anything in this Agreement to the contrary,
Section 13 shall not be applicable to a transaction described in subparagraphs
(x) and (y) of Section 13(a) if (i) such transaction is consummated with a
Person or Persons who acquired shares of Common Stock pursuant to a tender offer
or exchange offer for all outstanding shares of Common Stock which complies with
the provisions of Section 11(a)(ii)(B) hereof (or a wholly owned subsidiary of
any such Person or Persons), (ii) the price per share of Common Stock offered in
such transaction is not less than the price per share of Common Stock paid to
all holders of shares of Common Stock whose shares were purchased pursuant to
such tender offer or exchange offer, and (iii) the form of consideration being
offered to the remaining holders of shares of Common Stock pursuant to such
transaction is the same as the form of consideration paid pursuant to such
tender offer or exchange offer.  Upon consummation of any such transaction
contemplated by this Section 13(d), all Rights hereunder shall expire.

     Section 14.  Fractional Rights and Fractional Shares.
                  ----------------------------------------

          (a) The Company shall not be required to issue fractions of Rights,
except prior to the Distribution Date as provided in Section 11(p) hereof, or to
distribute Rights 

                                    - 26 -
<PAGE>
 
Certificates that evidence fractional Rights. If the Company determines not to
issue fractional Rights, there shall be paid in lieu thereof to the registered
holders of the Rights Certificates with regard to which such fractional Rights
would otherwise be issuable, an amount in cash equal to the same fraction of the
current market value of a whole Right. For purposes of this Section 14(a), the
current market value of a whole Right shall be the closing price of the Rights
for the Trading Day immediately prior to the date on which such fractional
Rights would have been otherwise issuable. The closing price of the Rights for
any day shall be the last sale price, regular way, or, in case no such sale
takes place on such day, the average of the closing bid and asked prices,
regular way, in either case as reported in the principal consolidated
transaction reporting system with respect to securities listed on the principal
national securities exchange on which the Rights are listed or admitted to
trading, or if the Rights are not listed or admitted to trading on any national
securities exchange, the last quoted price or, if not so quoted, the average of
the high bid and low asked prices in the over-the-counter market, as reported by
Nasdaq or such other system then in use or, if on any such date the Rights are
not quoted by any such organization, the average of the closing bid and asked
prices as furnished by a professional market maker making a market in the Rights
selected by the Board. If on any such date no such market maker is making a
market in the Rights the fair value of the Rights on such date as determined in
good faith by the Board shall be used.

          (b) The Company shall not be required to issue fractions of shares of
Preferred Stock (other than fractions which are integral multiples of one one-
hundredth of a share of Preferred Stock) upon exercise of the Rights or to
distribute certificates that evidence fractional shares of Preferred Stock
(other than fractions which are integral multiples of one one-hundredth of a
share of Preferred Stock).  In lieu of fractional shares of Preferred Stock that
are not integral multiples of one one-hundredth of a share of Preferred Stock,
the Company may pay to the registered holders of Rights Certificates, with
regard to which such fractional shares of Preferred Stock would otherwise be
issuable, at the time such Rights are exercised as herein provided, an amount in
cash equal to the same fraction of the current market value of one one-hundredth
of a share of Preferred Stock.  For purposes of this Section 14(b), the current
market value of one one-hundredth share of Preferred Stock shall be one one-
hundredth of the closing price per share of Common Stock (determined pursuant to
Section 11(d)(ii) hereof) on the Trading Day immediately prior to the date of
such exercise.

          (c) Following the occurrence of a Triggering Event, the Company shall
not be required to issue fractions of shares of Common Stock upon exercise of
the Rights or to distribute certificates which evidence fractional shares of
Common Stock.  In lieu of fractional shares of Common Stock, the Company may pay
to the registered holders of Rights Certificates at the time such Rights are
exercised as herein provided an amount in cash equal to the same fraction of the
current market value of one share of Common Stock.  For purposes of this Section
14(c), the current market value of one share of Common Stock shall be the
closing price of one share of Common Stock (as determined pursuant to Section
11(d)(i) hereof) for the Trading Day immediately prior to the date of such
exercise.

                                    - 27 -
<PAGE>
 
             (d) The holder of a Right by the acceptance of the Right expressly
waives his right to receive any fractional Rights or any fractional shares upon
exercise of a Right, except as permitted by this Section 14.

     Section 15.  Rights of Action.  All rights of action in respect of this
                  ----------------
Agreement, other than rights of action vested in the Rights Agent in Section 18
hereof, are vested in the respective registered holders of the Rights
Certificates (and, prior to the Distribution Date, the registered holders of the
Common Stock); and any registered holder of any Rights Certificate (or, prior to
the Distribution Date, of the Common Stock), without the consent of the Rights
Agent or of the holder of any other Rights Certificate (or, prior to the
Distribution Date, of the Common Stock), may, in his own behalf and for his own
benefit, enforce, and may institute and maintain any suit, action or proceeding
against the Company to enforce, or otherwise act in respect of, his right to
exercise the Rights evidenced by such Rights Certificate in the manner provided
in such Rights Certificate and in this Agreement. Without limiting the foregoing
or any remedies available to the holders of Rights, it is specifically
acknowledged that the holders of Rights would not have an adequate remedy at law
for any breach of this Agreement and shall be entitled to specific performance
of the obligations hereunder and injunctive relief against actual or threatened
violations of the obligations hereunder of any Person subject to this Agreement.

     Section 16.  Agreement of Rights Holders. Every holder of a Right, by
                  ---------------------------
accepting the same, consents and agrees with the Company and the Rights Agent
and with every other holder of a Right that:

             (a) prior to the Distribution Date, the Rights will be transferable
only in connection with the transfer of Common Stock;

             (b) after the Distribution Date, the Rights Certificates are
transferable only on the registry books of the Rights Agent if surrendered at
the principal office or offices of the Rights Agent designated for such
purposes, duly endorsed or accompanied by a proper instrument of transfer and
with the appropriate forms of assignment and certificates duly completed and
fully executed;

             (c) subject to Section 6(a) and Section 7(f) hereof, the Company
and the Rights Agent may deem and treat the person in whose name a Rights
Certificate (or, prior to the Distribution Date, the associated Common Stock
certificate) is registered as the absolute owner thereof and of the Rights
evidenced thereby (notwithstanding any notations of ownership or writing on the
Rights Certificates or the associated Common Stock certificate made by anyone
other than the Company or the Rights Agent) for all purposes whatsoever, and
neither the Company nor the Rights Agent, subject to the last sentence of
Section 7(e) hereof, shall be required to be affected by any notice to the
contrary; and

             (d) notwithstanding anything in this Agreement to the contrary,
neither the Company nor the Rights Agent shall have any liability to any holder
of a Right or other Person as a result of its inability to perform any of its
obligations under this Agreement by reason of any preliminary or permanent
injunction or other order, decree or ruling issued by a court of 

                                      28
<PAGE>
 
competent jurisdiction or by a governmental, regulatory or administrative agency
or commission, or any statute, rule, regulation or executive order promulgated
or enacted by any governmental authority, prohibiting or otherwise restraining
performance of such obligation; provided, however, the Company must use its best
                                --------  -------
efforts to have any such order, decree or ruling lifted or otherwise overturned
as soon as possible.

     Section 17.  Rights Certificate Holder Not Deemed a Stockholder.
                  --------------------------------------------------
No holder, as such, of any Rights Certificate shall be entitled to vote, receive
dividends or be deemed for any purpose the holder of the number of one one-
hundredths of a share of Preferred Stock or any other securities of the Company
which may at any time be issuable on the exercise of the Rights represented
thereby, nor shall anything contained herein or in any Rights Certificate be
construed to confer upon the holder of any Rights Certificate, as such, any of
the rights of a stockholder of the Company or any right to vote for the election
of directors or upon any matter submitted to stockholders at any meeting
thereof, or to give or withhold consent to any corporate action, or to receive
notice of meetings or other actions affecting stockholders (except as provided
in Section 25 hereof), or to receive dividends or subscription rights, or
otherwise, until the Right or Rights evidenced by such Rights Certificate shall
have been exercised in accordance with the provisions hereof.

     Section 18.  Concerning the Rights Agent.
                  ---------------------------

             (a) The Company agrees to pay to the Rights Agent reasonable
compensation for all services rendered by it hereunder and, from time to time,
on demand of the Rights Agent, its reasonable expenses and counsel fees and
disbursements and other disbursements incurred in the administration and
execution of this Agreement and the exercise and performance of its duties
hereunder.  The Company also agrees to indemnify the Rights Agent for, and to
hold it harmless against, any loss, liability or expense, incurred without
negligence, bad faith or willful misconduct on the part of the Rights Agent, for
anything done or omitted by the Rights Agent in connection with the acceptance
and administration of this Agreement, including the costs and expenses of
defending against any claim of liability in the premises.

             (b) The Rights Agent shall be protected and shall incur no
liability for or in respect of any action taken, suffered or omitted by it in
connection with its administration of this Agreement in reliance upon any Rights
Certificate or certificate for Common Stock or for other securities of the
Company, instrument of assignment or transfer, power of attorney, endorsement,
affidavit, letter, notice, direction, consent, certificate, statement, or other
paper or document believed by it to be genuine and to be signed, executed and,
where necessary, verified or acknowledged, by the proper Person or Persons.

     Section 19.  Merger or Consolidation or Change of Name of Rights Agent.
                  ---------------------------------------------------------

             (a) Any corporation into which the Rights Agent or any successor
Rights Agent may be merged or with which it may be consolidated, or any
corporation resulting from any merger or consolidation to which the Rights Agent
or any successor Rights Agent shall be a party, or any corporation succeeding to
the corporate trust or stock transfer business of the Rights 

                                     -29-
<PAGE>
 
Agent or any successor Rights Agent, shall be the successor to the Rights Agent
under this Agreement without the execution or filing of any paper or any further
act on the part of any of the parties hereto; provided, however, that such
                                              --------  -------
corporation would be eligible for appointment as a successor Rights Agent under
the provisions of Section 21 hereof. In case at the time such successor Rights
Agent shall succeed to the agency created by this Agreement, any of the Rights
Certificates shall have been countersigned but not delivered, any such successor
Rights Agent may adopt the counter-signature of a predecessor Rights Agent and
deliver such Rights Certificates so countersigned; and in case at that time any
of the Rights Certificates shall not have been countersigned, any successor
Rights Agent may countersign such Rights Certificates either in the name of the
predecessor or the name of the successor Rights Agent; and in all such cases
such Rights Certificates shall have the full force provided in the Rights
Certificates and in this Agreement.

             (b) In case at any time the name of the Rights Agent shall be
changed and at such time any of the Rights Certificates shall have been
countersigned but not delivered, the Rights Agent may adopt the countersignature
under its prior name and deliver Rights Certificates so countersigned; and in
case at that time any of the Rights Certificates shall not have been
countersigned, the Rights Agent may countersign such Rights Certificates either
in its prior name or in its changed name; and in all such cases such Rights
Certificates shall have the full force provided in the Rights Certificates and
in this Agreement.

     Section 20.  Duties of Rights Agent. The Rights Agent undertakes the duties
                  ----------------------
and obligations imposed by this Agreement upon the following terms and
conditions, by all of which the Company and the holders of Rights Certificates,
by their acceptance thereof, shall be bound:

             (a) The Rights Agent may consult with legal counsel (who may be
legal counsel for the Company), and the opinion of such counsel shall be full
and complete authorization and protection to the Rights Agent as to any action
taken or omitted by it in good faith and in accordance with such opinion.

             (b) Whenever in the performance of its duties under this Agreement
the Rights Agent shall deem it necessary or desirable that any fact or matter
(including, without limitation, the identity of any Acquiring Person or Adverse
Person and the determination of Current Market Price) be proved or established
by the Company prior to taking or suffering any action hereunder, such fact or
matter (unless other evidence in respect thereof be herein specifically
prescribed) may be deemed to be conclusively proved and established by a
certificate signed by the President, any Vice President, the Treasurer, any
Assistant Treasurer, the Secretary or any Assistant Secretary of the Company and
delivered to the Rights Agent; and such certificate shall be full authorization
to the Rights Agent for any action taken or suffered in good faith by it under
the provisions of this Agreement in reliance upon such certificate.

             (c) The Rights Agent shall be liable hereunder only for its own
negligence, bad faith or willful misconduct.

                                     -30-
<PAGE>
 
             (d) The Rights Agent shall not be liable for or by reason of any of
the statements of fact or recitals contained in this Agreement or in the Rights
Certificates or be required to verify the same (except as to its
countersignature on such Rights Certificates), but all such statements and
recitals are and shall be deemed to have been made by the Company only.

             (e) The Rights Agent shall not be under any responsibility in
respect of the validity of this Agreement or the execution and delivery hereof
(except the due execution hereof by the Rights Agent) or in respect of the
validity or execution of any Rights Certificate (except its countersignature
thereof); nor shall it be responsible for any breach by the Company of any
covenant or condition contained in this Agreement or in any Rights Certificate;
nor shall it be responsible for any adjustment required under the provisions of
Section 11 or Section 13 hereof or responsible for the manner, method or amount
of any such adjustment or the ascertaining of the existence of facts that would
require any such adjustment (except with respect to the exercise of Rights
evidenced by Rights Certificates after receipt of a certificate describing any
such adjustment furnished in accordance with Section 12); nor shall it by any
act hereunder be deemed to make any representation or warranty as to the
authorization or reservation of any shares of Common Stock to be issued pursuant
to this Agreement or any Rights Certificate or as to whether any shares of
Common Stock will, when so issued, be validly authorized and issued, fully paid
and nonassessable.

             (f) The Company agrees that it will perform, execute, acknowledge
and deliver or cause to be performed, executed, acknowledged and delivered all
such further and other acts, instruments and assurances as may reasonably be
required by the Rights Agent for the carrying out or performing by the Rights
Agent of the provisions of this Agreement.

             (g) The Rights Agent is hereby authorized and directed to accept
instructions with respect to the performance of its duties hereunder from the
President, the Chief Financial Officer, any Vice President, the Secretary, any
Assistant Secretary, the Treasurer or any Assistant Treasurer of the Company,
and to apply to such officers for advice or instructions in connection with its
duties, and it shall not be liable for any action taken or suffered to be taken
by it in good faith in accordance with instructions of any such officer.

             (h) The Rights Agent and any stockholder, director, officer or
employee of the Rights Agent may buy, sell or deal in any of the Rights or other
securities of the Company or become pecuniarily interested in any transaction in
which the Company may be interested, or contract with or lend money to the
Company or otherwise act as fully and freely as though it were not Rights Agent
under this Agreement.  Nothing herein shall preclude the Rights Agent from
acting in any other capacity for the Company or for any other legal entity.

             (i) The Rights Agent may execute and exercise any of the rights or
powers hereby vested in it or perform any duty hereunder either itself or by or
through its attorneys or agents, and the Rights Agent shall not be answerable or
accountable for any act, default, neglect or misconduct of any such attorneys or
agents or for any loss to the Company resulting from any such act, default,
neglect or misconduct; provided, however, reasonable care was exercised in the
                       --------  -------                                      
selection and continued employment thereof.

                                     -31-
<PAGE>
 
             (j) No provision of this Agreement shall require the Rights Agent
to expend or risk its own funds or otherwise incur any financial liability in
the performance of any of its duties hereunder or in the exercise of its rights
if there shall be reasonable grounds for believing that repayment of such funds
or adequate indemnification against such risk or liability is not reasonably
assured to it.

             (k) If, with respect to any Rights Certificate surrendered to the
Rights Agent for exercise or transfer, the certificate contained in the form of
assignment or the form of election to purchase set forth on the reverse thereof,
as the case may be, has either not been completed or indicates an affirmative
response to clause 1 or 2 thereof, the Rights Agent shall not take any further
action with respect to such requested exercise of transfer without first
consulting with the Company.

     Section 21.  Change of Rights Agent. The Rights Agent or any successor
                  ----------------------
Rights Agent may resign and be discharged from its duties under this Agreement
upon thirty (30) days' notice in writing mailed to the Company, and to each
transfer agent of the Common Stock and Preferred Stock, by registered or
certified mail, and to the holders of the Rights Certificates by first-class
mail. The Company may remove the Rights Agent or any successor Rights Agent upon
thirty (30) days' notice in writing, mailed to the Rights Agent or successor
Rights Agent, as the case may be, and to each transfer agent of the Common Stock
and Preferred Stock, by registered or certified mail, and to the holders of the
Rights Certificates by first-class mail. If the Rights Agent shall resign or be
removed or shall otherwise become incapable of acting, the Company shall appoint
a successor to the Rights Agent. If the Company shall fail to make such
appointment within a period of thirty (30) days after giving notice of such
removal or after it has been notified in writing of such resignation or
incapacity by the resigning or incapacitated Rights Agent or by any registered
holder of a Rights Certificate (who shall, with such notice, submit his Rights
Certificate for inspection by the Company), then any registered holder of any
Rights Certificate may apply to any court of competent jurisdiction for the
appointment of a new Rights Agent. Any successor Rights Agent, whether appointed
by the Company or by such a court, shall be (a) a corporation organized and
doing business under the laws of the United States or any state thereof in good
standing, which is authorized under such laws to exercise corporate trust or
stock transfer powers and is subject to supervision or examination by federal or
state authority and which has at the time of its appointment as Rights Agent a
combined capital and surplus of at least $50,000,000 or (b) an affiliate of a
corporation described in clause (a) of this sentence. After appointment, the
successor Rights Agent shall be vested with the same powers, rights, duties and
responsibilities as if it had been originally named as Rights Agent without
further act or deed; but the predecessor Rights Agent shall deliver and transfer
to the successor Rights Agent any property at the time held by it hereunder, and
execute and deliver any further assurance, conveyance, act or deed necessary for
the purpose. Not later than the effective date of any such appointment, the
Company shall file notice thereof in writing with the predecessor Rights Agent
and each transfer agent of the Common Stock and Preferred Stock, and mail a
notice thereof in writing to the registered holders of the Rights Certificates.
Failure to give any notice provided for in this Section 21, however, or any
defect therein, shall not affect the legality 

                                     -32-
<PAGE>
 
or validity of the resignation or removal of the Rights Agent or the appointment
of the successor Rights Agent, as the case may be.

     Section 22.  Issuance of New Rights Certificates. Notwithstanding any of
                  -----------------------------------  
the provisions of this Agreement or of the Rights to the contrary, the Company
may, at its option, issue new Rights Certificates evidencing Rights in such form
as may be approved by the Board to reflect any adjustment or change in the
Purchase Price and the number or kind or class of shares or other securities or
property purchasable under the Rights Certificates made in accordance with the
provisions of this Agreement. In addition, in connection with the issuance or
sale of shares of Common Stock following the Distribution Date (other than upon
exercise of a Right) and prior to the redemption or expiration of the Rights,
the Company (a) shall, with respect to shares of Common Stock so issued or sold
pursuant to the exercise of stock options or under any employee plan or
arrangement, or upon the exercise, conversion or exchange of securities, notes,
warrants or debentures issued by the Company, and (b) may, in any other case, if
deemed necessary or appropriate by the Board, issue Rights Certificates
representing the appropriate number of Rights in connection with such issuance
or sale; provided, however, that (i) no such Rights Certificate shall be issued
         --------  -------
if, and to the extent that, the Company shall be advised by counsel that such
issuance would create a significant risk of material adverse tax consequences to
the Company or the Person to whom such Rights Certificate would be issued, and
(ii) no such Rights Certificate shall be issued if, and to the extent that,
appropriate adjustment shall otherwise have been made in lieu of the issuance
thereof.

     Section 23.  Redemption and Termination.
                  --------------------------

             (a) The Board may, at its option, at any time prior to the earlier
of (i) the Close of Business on the tenth day following the Stock Acquisition
Date (or, if the Stock Acquisition Date shall have occurred prior to the Record
Date, the close of business on the tenth day following the Record Date), or such
later date as may be determined by action of the Board (with the concurrence of
a majority of Continuing Directors), or (ii) the Final Expiration Date, redeem
all but not less than all of the then outstanding Rights at a redemption price
of $.01 per Right, as such amount may be appropriately adjusted to reflect any
stock split, stock dividend or similar transaction occurring after the date
hereof (such redemption price being hereinafter referred to as the "Redemption
                                                                    ----------  
Price"); provided, however, that the Board may not redeem any Rights following
- -----    --------  ------- 
an Adverse Person Event and provided, further, that if the Board authorizes
                            --------  -------
redemption of the Rights at or after the time a Person becomes an Acquiring
Person, then there must be Continuing Directors then in office and such
authorization shall require the concurrence of a majority of such Continuing
Directors. Notwithstanding anything contained in this Agreement to the contrary,
the Rights shall not be exercisable after the first occurrence of a Section
11(a)(ii) Event until such time as the Company's right of redemption set forth
in the first sentence of this Section 23(a) has expired. The Company may, at its
option, pay the Redemption Price in cash, shares of Common Stock (based on the
Current Market Price as defined in Section 11(d) hereof, of the Common Stock at
the time of redemption) or any other form of consideration deemed appropriate by
the Board. The redemption of the Rights by the Board may be made effective at
such time, on such basis and with such conditions as the Board in its sole
discretion may establish; provided, however, that if the Board authorizes
                          --------  ------- 
redemption of the 

                                     -33-
<PAGE>
 
Rights at or after the time a Person becomes an Acquiring Person, then there
must be Continuing Directors then in office and such terms and conditions shall
require the concurrence of a majority of such Continuing Directors.

             (b) Immediately upon the action of the Board ordering the
redemption of the Rights, evidence of which shall have been filed with the
Rights Agent and without any further action and without any notice, the right to
exercise the Rights will terminate and the only right thereafter of the holders
of Rights shall be to receive the Redemption Price for each Right so held.
Promptly after the action of the Board ordering the redemption of the Rights,
the Company shall give notice of such redemption to the Rights Agent and the
holders of the then outstanding Rights by mailing such notice to all such
holders at each holder's last address as it appears upon the registry books of
the Rights Agent or, prior to the Distribution Date, on the registry books of
the Transfer Agent for the Common Stock. Any notice which is mailed in the
manner herein provided shall be deemed given, whether or not the holder receives
the notice. Each such notice of the redemption will state the method by which
the payment of the Redemption Price will be made.

     Section 24.  Exchange.
                  --------

             (a) At any time after any Person becomes an Acquiring Person or an
Adverse Person, the Board (with the concurrence of a majority of the Continuing
Directors) may, at their option, exchange all or part of the then outstanding
and exercisable Rights (which (i) shall not include Rights that have become void
pursuant to Section 7(e) and (ii) shall include, without limitation, any Rights
issued after the Distribution Date in connection with the exercise of options
pursuant to any employee benefit plan of the Company or any Subsidiary of the
Company) for shares of Common Stock at an exchange ratio of one share of Common
Stock per Right, appropriately adjusted to reflect any stock split, stock
dividend or similar transaction occurring after the date hereof (such exchange
ratio being hereinafter referred to as the "Exchange Ratio").  Notwithstanding
                                            --------------                    
the foregoing, the Board of Directors shall not be empowered to effect such
exchange at any time after any Person (other than the Company, any of its
Subsidiaries, any employee benefit plan of the Company or any of its
Subsidiaries or any Person organized, appointed or established by the Company or
any of its Subsidiaries for or pursuant to the terms of any such plan), together
with all Affiliates and Associates of such Person, becomes the Beneficial Owner
of 50% or more of the shares of Common Stock then outstanding.

             (b) Immediately upon the action of the Board electing to exchange
any Rights pursuant to Section 24(a) and without any further action and without
any notice, the right to exercise such Rights will terminate and thereafter the
only right of a holder of such Rights shall be to receive that number of shares
of Common Stock equal to the number of such Rights held by such holder
multiplied by the Exchange Ratio. The Company shall promptly thereafter give
notice of such exchange to the Rights Agent and the holders of the Rights to be
exchanged in the manner set forth in Section 26; provided, however, that the
                                                 --------  -------
failure to give, or any defect in, such notice shall not affect the validity of
such exchange. Any notice which is mailed in the manner herein provided shall be
deemed given, whether or not the holder receives the notice. Each such 

                                     -34-
<PAGE>
 
notice of exchange will state the method by which the exchange of the shares of
Common Stock for Rights will be effected and, in the event of any partial
exchange, the number of Rights which will be exchanged. Any partial exchange
shall be effected pro rata based on the number of Rights (other than Rights
which have become void pursuant to Section 7(e)) held by each holder of Rights.

             (c) In any exchange pursuant to this Section 24, the Company, at
its option, may substitute Common Stock Equivalents (as defined in Section
11(a)(iii)) for shares of Common Stock exchangeable for Rights, at the initial
rate of one Common Stock Equivalent for each share of Common Stock, as
appropriately adjusted to reflect adjustments in dividend, liquidation and
voting rights of Common Stock Equivalents pursuant to the terms thereof, so that
each Common Stock Equivalent delivered in lieu of each share of Common Stock
shall have essentially the same dividend, liquidation and voting rights as one
share of Common Stock.

             (d) In the event that the number of shares of Common Stock which
are authorized by the Company's certificate of incorporation but not outstanding
or reserved for issuance are not sufficient to permit an exchange of Rights as
contemplated by this Section 24, the Company shall take all such action as may
be necessary to authorize additional shares of Common Stock for issuance upon
exchange of the Rights.

             (e) The Company shall not be required to issue fractions of shares
of Common Stock or to distribute certificates that evidence fractional shares of
Common Stock. In lieu of fractional shares of Common Stock, the Company may pay
to the registered holders of Rights Certificates with regard to which such
fractional shares of Common Stock would otherwise be issuable, an amount in cash
equal to the same fraction of the current market value of a whole share of
Common Stock. For purposes of this Section 24(e), the current market value of a
whole share of Common Stock shall be the closing price per share of Common Stock
(determined pursuant to Section 11(d)(ii) hereof) on the Trading Day immediately
prior to the date of exchange pursuant to this Section 24.

     Section 25.  Notice of Certain Events.
                  ------------------------

             (a) In case the Company shall propose, at any time after the
Distribution Date, (i) to pay any dividend payable in stock of any class to the
holders of Preferred Stock or to make any other distribution to the holders of
Preferred Stock (other than a regular quarterly cash dividend out of earnings or
retained earnings of the Company), or (ii) to offer to the holders of Preferred
Stock rights or warrants to subscribe for or to purchase any additional shares
of Preferred Stock or shares of stock of any class or any other securities,
rights or options, or (iii) to effect any reclassification of its Preferred
Stock (other than a reclassification involving only the subdivision of
outstanding shares of Preferred Stock), or (iv) to effect any consolidation or
merger into or with any other Person (other than a Subsidiary of the Company in
a transaction which complies with Section 11(o) hereof), or to effect any sale
or other transfer (or to permit one or more of its Subsidiaries to effect any
sale or other transfer), in one transaction or a series of related transactions,
of more than 50% of the assets or earning power of the Company and its
Subsidiaries (taken as a whole) to any other Person or Persons (other than the
Company or any of 

                                     -35-
<PAGE>
 
its Subsidiaries in one or more transactions each of which complies with Section
11(o) hereof), or (v) to effect the liquidation, dissolution or winding up of
the Company, then, in each such case, the Company shall give to each holder of a
Rights Certificate, to the extent feasible, in accordance with Section 26
hereof, a notice of such proposed action, which shall specify the record date
for the purposes of such stock dividend or distribution of rights or warrants,
or the date on which such reclassification, consolidation, merger, sale,
transfer, liquidation, dissolution, or winding up is to take place and the date
of participation therein by the holders of the shares of Preferred Stock, if any
such date is to be fixed, and such notice shall be so given in the case of any
action covered by clause (i) or (ii) above at least twenty (20) days prior to
the record date for determining holders of the shares of Preferred Stock for
purposes of such action, and in the case of any such other action, at least
twenty (20) days prior to the date of the taking of such proposed action or the
date of participation therein by the holders of the shares of Preferred Stock,
whichever shall be the earlier.

             (b) In case any Section 11(a)(ii) Event shall occur, then, in any
such case, (i) the Company shall as soon as practicable thereafter give to each
holder of a Rights Certificate, to the extent feasible, and in accordance with
Section 26 hereof, a notice of the occurrence of such event, which shall specify
the event and the consequences of the event to holders of Rights under Section
11(a)(ii) hereof and (ii) all references in the preceding paragraph to Common
Stock shall, to the extent appropriate, also be deemed thereafter to refer to
other securities.

     Section 26.  Notices. Notices or demands authorized by this Agreement to be
                  -------
given or made by the Rights Agent or by the holder of any Rights Certificate to
or on the Company shall be sufficiently given or made if sent by first-class
mail, postage prepaid, addressed (until another address is filed in writing with
the Rights Agent) as follows:

               Cytyc Corporation
               85 Swanson Road
               Boxborough, MA  01719
               Attn:  President and Chief Executive Officer

Subject to the provisions of Section 21, any notice or demand authorized by this
Agreement to be given or made by the Company or by the holder of any Rights
Certificate to or on the Rights Agent shall be sufficiently given or made if
sent by first-class mail, postage prepaid, addressed (until another address is
filed in writing with the Company) as follows:

               BankBoston, N.A.
               c/o Boston EquiServe Limited Partnership
               150 Royall Street
               Canton, MA  02021
               Attn:  William J. Chouinard

Notices or demands authorized by this Agreement to be given or made by the
Company or the Rights Agent to the holder of any Rights Certificate (or, if
prior to the Distribution Date, to the holder of certificates representing
shares of Common Stock) shall be sufficiently given or made 

                                     -36-
<PAGE>
 
if sent by first-class mail, postage prepaid, addressed to such holder at the
address of such holder as shown on the registry books of the Company.

     Section 27.  Supplements and Amendments. At any time prior to the Final
                  -------------------------- 
Amendment Date, and subject to the penultimate sentence of this Section 27, the
Company and the Rights Agent shall, if the Company so directs, supplement or
amend any provision of this Agreement without the approval of any holders of
certificates representing shares of Common Stock. From and after the Final
Amendment Date and subject to the penultimate sentence of this Section 27, the
Company may (acting by at least a majority of the Continuing Directors) and the
Rights Agent shall, if the Company so directs, supplement or amend this
Agreement without the approval of any holders of Rights Certificates in order
(i) to cure any ambiguity, (ii) to correct or supplement any provision contained
herein which may be defective or inconsistent with any other provisions herein,
(iii) to shorten or lengthen any time period hereunder (which lengthening or
shortening, following the first occurrence of an event set forth in the second
proviso of the first sentence of Section 23(a) hereof, shall be effective only
if there are Continuing Directors and shall require the concurrence of a
majority of such Continuing Directors) or (iv) to change or supplement the
provisions hereunder in any manner which the Company may deem necessary or
desirable and which shall not adversely affect the interests of the holders of
Rights Certificates (other than an Acquiring Person, an Adverse Person or an
Affiliate or Associate of such Person); provided, however, that this Agreement
                                        --------  -------
may not be supplemented or amended, pursuant to clause (iii) of this sentence to
lengthen (A) a time period relating to when the Rights may be redeemed or at
such time as the Rights are not then redeemable or (B) any other time period
unless such lengthening is for the purpose of protecting, enhancing or
clarifying the rights of or the benefits to the holders of Rights (other than
any Acquiring Person, an Adverse Person or an Associate or Affiliate of such
Person). Upon the delivery of a certificate from an appropriate officer of the
Company which states that the proposed supplement or amendment is in compliance
with the terms of this Section 27, the Rights Agent shall execute such
supplement or amendment. Prior to the Distribution Date, the interests of the
holders of Rights shall be deemed coincident with the interests of the holders
of Common Stock.

     Section 28.  Successors. All the covenants and provisions of this Agreement
                  ----------
by or for the benefit of the Company or the Rights Agent shall bind and inure to
the benefit of their respective successors and assigns hereunder.

     Section 29.  Determinations and Actions by the Board of Directors, etc. For
                  ---------------------------------------------------------
all purposes of this Agreement, any calculation of the number of shares of
Common Stock outstanding at any particular time, including for purposes of
determining the particular percentage of such outstanding shares of Common Stock
of which any Person is the Beneficial Owner, shall be made in accordance with
the provisions of the last sentence of Rule 13d-3(d)(l)(i) of the General Rules
and Regulations under the Exchange Act. The Board (with, where specifically
provided for herein, the concurrence of the Continuing Directors) shall have the
exclusive power and authority to administer this Agreement and to exercise all
rights and powers specifically granted to the Board (with, where specifically
provided for herein, the concurrence of the Continuing Directors) or to the
Company, or as may be necessary or advisable in the administration of this
Agreement, including, without limitation, the right and power to (i) interpret
the provisions of 

                                     -37-
<PAGE>
 
this Agreement, and (ii) make all determinations deemed necessary or advisable
for the administration of this Agreement (including a determination to redeem or
not redeem the Rights, to declare that a Person is an Adverse Person or to amend
the Agreement). All such actions, calculations, interpretations and
determinations (including, for purposes of clause (y) below, all omissions with
respect to the foregoing) which are done or made by the Board (with, where
specifically provided for herein, the concurrence of the Continuing Directors)
in good faith, shall (x) be final, conclusive and binding on the Company, the
Rights Agent, the holders of the Rights and all other parties, and (y) not
subject any member of the Board or any Continuing Director of the Company to any
liability to the holders of the Rights. Notwithstanding anything to the contrary
in this Agreement, from and after the election of directors of the Company at
the first annual meeting of stockholders of the Company called after the time a
Person becomes an Acquiring Person, all provisions of this Agreement that
require the action or concurrence of the Continuing Directors shall no longer
require the action or concurrence of the Continuing Directors but instead shall
require only the action of a majority of the Board.

     Section 30.  Benefits of this Agreement. Nothing in this Agreement shall be
                  --------------------------
construed to give to any Person other than the Company, the Rights Agent and the
registered holders of the Rights Certificates (and, prior to the Distribution
Date, registered holders of the Common Stock) any legal or equitable right,
remedy or claim under this Agreement; but this Agreement shall be for the sole
and exclusive benefit of the Company, the Rights Agent and the registered
holders of the Rights Certificates (and, prior to the Distribution Date,
registered holders of the Common Stock).

     Section 31.  Severability.  If any term, provision, covenant or restriction
                  ------------ 
of this Agreement is held by a court of competent jurisdiction or other
authority to be invalid, void or unenforceable, the remainder of the terms,
provisions, covenants and restrictions of this Agreement shall remain in full
force and effect and shall in no way be affected, impaired or invalidated,
provided, however, that notwithstanding anything in this Agreement to the
contrary, if any such term, provision, covenant or restriction is held by such
court or authority to be invalid, void or unenforceable and the Board determines
in its good faith judgment that severing the invalid language from this
Agreement would materially and adversely affect the purpose or effect of this
Agreement, the right of redemption set forth in Section 23 hereof shall be
reinstated and shall not expire until the close of business on the tenth day
following the date of such determination by the Board. Without limiting the
foregoing, if any provision requiring that a determination made by less than the
entire Board is held by a court of competent jurisdiction or other authority to
be invalid, void or unenforceable, such determination shall then be made by the
entire Board.

     Section 32.  Governing Law.  This Agreement, each Right and each Rights
                  -------------
Certificate issued hereunder shall be deemed to be a contract made under the
laws of the State of Delaware and for all purposes shall be governed by and
construed in accordance with the laws of such State applicable to contracts made
and to be performed entirely within such State.

                                     -38-
<PAGE>
 
     Section 33.  Counterparts. This Agreement may be executed in any number of
                  ------------
counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and all such counterparts shall together constitute but one and
the same instrument.

     Section 34.  Descriptive Headings. Descriptive headings of the several
                  -------------------- 
Sections of this Agreement are inserted for convenience only and shall not
control or affect the meaning or construction of any of the provisions hereof.


             [THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]




                                     -39-
<PAGE>
 
          IN WITNESS WHEREOF, the parties hereto have caused this Rights
Agreement to be duly executed and their respective corporate seals to be
hereunto affixed and attested, all as of the day and year first above written.

Attest:                                    CYTYC CORPORATION



By: /s/ Joseph E. Kelly                   By: /s/ Patrick J. Sullivan 
   --------------------------------           ----------------------------------
   Name:  Joseph W. Kelly                     Name:  Patrick J. Sullivan
   Title:  Chief Financial Officer            Title:  President and Chief 
                                                      Executive Officer


Attest:                                   BANKBOSTON, N.A., as Rights Agent

By: /s/ William J. Chouinard                  By: /s/ Michael Lapolla
   --------------------------------           ----------------------------------
Name:  William J. Chouinard                   Name:  Michael Lapolla
     ------------------------------                -----------------------------
Title: Account Manager                        Title: Director, Client Services
      -----------------------------                 ----------------------------

                                     -40- 
<PAGE>
 
                                                                       EXHIBIT A
                                                                       ---------

                          CERTIFICATE OF DESIGNATIONS

                 SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                              --------------------

                               ($0.01 Par Value)
                                       of
                               CYTYC CORPORATION

                              --------------------

                         Pursuant to Section 151 of the
                General Corporation Law of the State of Delaware

                              --------------------

          Cytyc Corporation, a corporation organized and existing under the
General Corporation Law of the State of Delaware (the "Corporation"), in
accordance with the provisions of Section 103 thereof, DOES HEREBY CERTIFY:

          FIRST:  That pursuant to the authority conferred upon the Board of
Directors by the Certificate of Incorporation of the Corporation, the Board of
Directors of the Corporation adopted the following resolutions creating a series
of 200,000 shares of Preferred Stock, $0.01 par value per share, designated as
Series A Junior Participating Preferred Stock:

          RESOLVED:  That pursuant to the authority vested in the Board of
                     Directors of this Corporation in accordance with the
                     provisions of Article FOURTH, Section B, of its Certificate
                     of Incorporation, a series of Preferred Stock of the
                     Corporation (the "Series A Junior Participating Preferred
                     Stock") be, and it hereby is, created, and that the
                     designation and amount thereof and the voting powers,
                     preferences and relative, participating, optional and other
                     special rights of the shares of the Series A Junior
                     Participating Preferred Stock, and the qualifications,
                     limitations or restrictions thereof, shall be as set forth
                     in Appendix A attached hereto.
                        ----------                 

          RESOLVED:  That the President, Chief Financial Officer or any Vice
                     President and the Secretary or any Assistant Secretary of
                     the Corporation be, and they hereby are, authorized and
                     directed, in the name and on behalf of the Corporation, to
                     file the Certificate of Designations in accordance with the
                     provisions of Delaware General Corporation Law and to take
                     such actions as they may deem necessary or appropriate to
                     carry out the intent of the foregoing resolution.
<PAGE>
 
          SECOND:  That the aforesaid resolutions were duly and validly adopted
in accordance with the applicable provisions of Section 151 of the General
Corporation Law of the State of Delaware and the Certificate of Incorporation
and By-Laws of the Corporation.

          THIRD:  That the aforesaid designation shall become effective on
August 27, 1997.
<PAGE>
 
                                                                      Appendix A
                                                                      ----------

     Section 1.  Designation and Amount.  The shares of such series shall be
                 ----------------------                                     
designated as "Series A Junior Participating Preferred Stock" and the number of
shares constituting such series shall be 200,000.  Such number of shares may be
increased or decreased by resolution of the Board of Directors; provided,
                                                                -------- 
however, that no decrease shall reduce the number of shares of Series A Junior
- -------                                                                       
Participating Preferred Stock to a number less than the number of shares then
outstanding plus the number of shares reserved for issuance upon the exercise of
outstanding options, rights or warrants or upon the conversion of any
outstanding securities issued by the Corporation convertible into Series A
Junior Participating Preferred Stock.

     Section 2.  Dividends and Distributions.
                 --------------------------- 

          (A) Subject to the rights of the holders of any shares of any series
of Preferred Stock ranking prior and superior to the shares of Series A Junior
Participating Preferred Stock with respect to dividends, the holders of shares
of Series A Junior Participating Preferred Stock, in preference to the holders
of Common Stock, $.01 par value per share and Class A Stock, $.01 par value per
share collectively the "Common Stock"), of the Corporation, and of any other
junior stock, shall be entitled to receive, when, as and if declared by the
Board of Directors, out of funds of the Corporation legally available for the
payment of dividends, quarterly dividends payable in cash on January 31, April
30, July 31 and October 31 in each year (each such date being referred to herein
as a "Quarterly Dividend Payment Date"), commencing on the first Quarterly
Dividend Payment Date after the first issuance of a share or fraction of a share
of Series A Junior Participating Preferred Stock, in an amount per share
(rounded to the nearest cent) equal to the greater of (a) $1.00 or (b) subject
to the provision for adjustment hereinafter set forth, 100 times the aggregate
per share amount of all cash dividends, and 100 times the aggregate per share
amount (payable in kind) of all non-cash dividends or other distributions, other
than a dividend payable in shares of Common Stock or a subdivision of the
outstanding shares of Common Stock (by reclassification or otherwise), declared
on the Common Stock since the immediately preceding Quarterly Dividend Payment
Date, or, with respect to the first Quarterly Dividend Payment Date, since the
first issuance of any share or fraction of a share of Series A Junior
Participating Preferred Stock.  In the event the Corporation shall at any time
declare or pay any dividend on Common Stock payable in shares of Common Stock or
effect a subdivision, combination or consolidation of the outstanding Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the amount to which holders of shares of Series A Junior
Participating Preferred Stock were entitled immediately prior to such event
under clause (b) of the preceding sentence shall be adjusted by multiplying such
amount by a fraction, the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is
the number of shares of Common Stock that were outstanding immediately prior to
such event.

          (B) The Corporation shall declare a dividend or distribution on the
Series A Junior Participating Preferred Stock as provided in paragraph (A) above
immediately after it declares a dividend or distribution on the Common Stock
(other than a dividend payable in 
<PAGE>
 
shares of Common Stock) and the Corporation shall pay such dividend or
distribution on the Series A Junior Participating Preferred Stock before the
dividend or distribution declared on the Common Stock is paid or set apart;
provided, however, that, in the event no dividend or distribution shall have
- --------  -------
been declared on the Common Stock during the period between any Quarterly
Dividend Payment Date and the next subsequent Quarterly Dividend Payment Date, a
dividend of $1.00 per share on the Series A Junior Participating Preferred Stock
shall nevertheless be payable on such subsequent Quarterly Dividend Payment
Date.

          (C) Dividends shall begin to accrue and be cumulative on outstanding
shares of Series A Junior Participating Preferred Stock from the Quarterly
Dividend Payment Date next preceding the date of issue of such shares of Series
A Junior Participating Preferred Stock, unless the date of issue of such shares
is prior to the record date for the first Quarterly Dividend Payment Date, in
which case dividends on such shares shall begin to accrue from the date of issue
of such shares, or unless the date of issue is a Quarterly Dividend Payment Date
or is a date after the record date for the determination of holders of shares of
Series A Junior Participating Preferred Stock entitled to receive a quarterly
dividend and before such Quarterly Dividend Payment Date, in either of which
events such dividends shall begin to accrue and be cumulative from such
Quarterly Dividend Payment Date.  Accrued but unpaid dividends shall not bear
interest.  Dividends paid on the shares of Series A Junior Participating
Preferred Stock in an amount less than the total amount of such dividends at the
time accrued and payable on such shares shall be allocated pro rata on a share-
by-share basis among all such shares at the time outstanding.  The Board of
Directors may fix a record date for the determination of holders of shares of
Series A Junior Participating Preferred Stock entitled to receive payment of a
dividend or distribution declared thereon, which record date shall be no more
than 60 days prior to the date fixed for the payment thereof.

     Section 3.  Voting Rights.  The holders of shares of Series A Junior
                 -------------                                           
Participating Preferred Stock shall have the following voting rights:

          (A) Subject to the provision for adjustment hereinafter set forth,
each share of Series A Junior Participating Preferred Stock shall entitle the
holder thereof to 100 votes on all matters submitted to a vote of the
stockholders of the Corporation.  In the event the Corporation shall at any time
declare or pay any dividend on Common Stock payable in shares of Common Stock or
effect a subdivision, combination of consolidation of the outstanding Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the number of votes per share to which holders of shares of
Series A Junior Participating Preferred Stock were entitled immediately prior to
such event shall be adjusted by multiplying such number by a fraction, the
numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

          (B) Except as otherwise provided herein, by law, or in any other
Certificate of Designations creating a series of Preferred Stock or any similar
stock, the holders of shares of Series A Junior Participating Preferred Stock,
the holders of shares of Common Stock and any 
<PAGE>
 
other capital stock of the Corporation having general voting rights shall vote
together as one class on all matters submitted to a vote of stockholders of the
Corporation.

          (C) (i) If at any time dividends on any Series A Junior Participating
Preferred Stock shall be in arrears in an amount equal to six (6) quarterly
dividends thereon, the occurrence of such contingency shall mark the beginning
of a period (herein called a "default period") which shall extend until such
time when all accrued and unpaid dividends for all previous quarterly dividend
periods and for the current quarterly dividend period on all shares of Series A
Junior Participating Preferred Stock then outstanding shall have been declared
and paid or set apart for payment.  During each default period, all holders of
Preferred Stock (including holders of the Series A Junior Participating
Preferred Stock) with dividends in arrears in an amount equal to six (6)
quarterly dividends thereon, voting as a class, irrespective of series, shall
have the right to elect two (2) Directors.

              (ii)   During any default period, such voting right of the holders
of Series A Junior Participating Preferred Stock may be exercised initially at a
special meeting called pursuant to subparagraph (iii) of this Section 3(C) or at
any annual meeting of stockholders, and thereafter at annual meetings of
stockholders, provided that neither such voting right nor the right of the
holders of any other series of Preferred Stock, if any, to increase, in certain
cases, the authorized number of Directors shall be exercised unless the holders
of ten percent (10%) in number of shares of Preferred Stock outstanding shall be
present in person or by proxy. The absence of a quorum of the holders of Common
Stock shall not affect the exercise by the holders of Preferred Stock of such
voting right. At any meeting at which the holders of Preferred Stock shall
exercise such voting right initially during an existing default period, they
shall have the right, voting as a class, to elect Directors to fill such
vacancies, if any, in the Board of Directors as may then exist up to two (2)
Directors or, if such right is exercised at an annual meeting, to elect two (2)
Directors. If the number which may be so elected at any special meeting does not
amount to the required number, the holders of the Preferred Stock shall have the
right to make such increase in the number of Directors as shall be necessary to
permit the election by them of the required number. After the holders of the
Preferred Stock shall have exercised their right to elect Directors in any
default period and during the continuance of such period, the number of
Directors shall not be increased or decreased except by vote of the holders of
Preferred Stock as herein provided or pursuant to the rights of any equity
securities ranking senior to or pari passu with the Series A Junior 
                                ---- -----                         
Participating Preferred Stock.

              (iii)  Unless the holders of Preferred Stock shall, during an
existing default period, have previously exercised their right to elect
Directors, the Board of Directors may order, the calling of special meeting of
the holders of Preferred Stock, which meeting shall thereupon be called by the
Chairman of the Board or the President, of the Corporation.  Notice of such
meeting and of any annual meeting at which holders of Preferred Stock are
entitled to vote pursuant to this paragraph (C)(iii) shall be given to each
holder of record of Preferred Stock by mailing a copy of such notice to him at
his last address as the same appears on the books of the Corporation.  Such
meeting shall be called for a time not earlier than 10 days and not later than
60 days after such order or request. Notwithstanding the provisions of this
paragraph (C)(iii), no 
<PAGE>
 
such special meeting shall be called during the period within 60 days
immediately preceding the date fixed for the next annual meeting of the
stockholders.

              (iv) In any default period, the holders of Common Stock, and other
classes of stock of the Corporation if applicable, shall continue to be entitled
to elect the whole number of Directors until the holders of Preferred Stock
shall have exercised their right to elect two (2) Directors voting as a class,
after the exercise of which right (x) the Directors so elected by the holders of
Preferred Stock shall continue in office until their successors shall have been
elected by such holders or until the expiration of the default period, and (y)
any vacancy in the Board of Directors may (except as provided in paragraph
(C)(ii) of this Section 3) be filled by vote of a majority of the remaining
Directors theretofore elected by the holders of the class of stock which elected
the Director whose office shall have become vacant.  References in this
paragraph (C) to Directors elected by the holders of a particular class of stock
shall include Directors elected by such Directors to fill vacancies as provided
in clause (y) of the foregoing sentence.

              (v)  Immediately upon the expiration of a default period, (x) the
right of the holders of Preferred Stock as a class to elect Directors shall
cease, (y) the term of any Directors elected by the holders of Preferred Stock
as a class shall terminate, and (z) the number of Directors shall be such number
as may be provided for in the certificate of incorporation or by-laws
irrespective of any increase made pursuant to the provisions of paragraph
(C)(ii) of this Section 3 (such number being subject, however, to change
thereafter in any manner provided by law or in the certificate of incorporation
or bylaws). Any vacancies in the Board of Directors effected by the provisions
of clauses (y) and (z) in the preceding sentence may be filled by a majority of
the remaining Directors.

          (D) Except as set forth herein, or as otherwise provided by law,
holders of Series A Junior Participating Preferred Stock shall have no special
voting rights and their consent shall not be required (except to the extent they
are entitled to vote with holders of Common Stock as set forth herein) for
taking any corporate action.

     Section 4.  Certain Restrictions.
                 -------------------- 

          (A) Whenever quarterly dividends or other dividends or distributions
payable on the Series A Junior Participating Preferred Stock as provided in
Section 2 are in arrears, thereafter and until all accrued and unpaid dividends
and distributions, whether or not declared, on shares of Series A Junior
Participating Preferred Stock outstanding shall have been paid in full, the
Corporation shall not:

              (i)  declare or pay dividends on or make any other distributions
on any shares of stock ranking junior (either as to dividends or upon
liquidation, dissolution or winding up) to the Series A Junior Participating
Preferred Stock;

              (ii) declare or pay dividends on or make any other distributions
on any shares of stock ranking on a parity (either as to dividends or upon
liquidation, dissolution or 
<PAGE>
 
winding up) with the Series A Junior Participating Preferred Stock, except
dividends paid ratably on the Series A Junior Participating Preferred Stock and
all such parity stock on which dividends are payable or in arrears in proportion
to the total amounts to which the holders of all such shares are then entitled;

              (iii)  redeem or purchase or otherwise acquire for consideration
shares of any stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Series A Junior Participating Preferred Stock,
provided that the Corporation may at any time redeem, purchase or otherwise
acquire shares of any such junior stock in exchange for shares of any stock of
the Corporation ranking junior (either as to dividends or upon dissolution,
liquidation or winding up) to the Series A Junior Participating Preferred Stock;

              (iv)   purchase or otherwise acquire for consideration any shares
of Series A Junior Participating Preferred Stock, or any shares of stock ranking
on a parity with the Series A Junior Participating Preferred Stock, except in
accordance with a purchase offer made in writing or by publication (as
determined by the Board of Directors) to all holders of such shares upon such
terms as the Board of Directors, after consideration of the respective annual
dividend rates and other relative rights and preferences of the respective
series and classes, shall determine in good faith will result in fair and
equitable treatment among the respective series or classes.

          (B) The Corporation shall not permit any subsidiary of the Corporation
to purchase or otherwise acquire for consideration any shares of stock of the
Corporation unless the Corporation could, under paragraph (A) of this Section 4,
purchase or otherwise acquire such shares at such time and in such manner.

     Section 5.  Reacquired Shares.  Any shares of Series A Junior Participating
                 -----------------                                              
Preferred Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever shall be retired and canceled promptly after the acquisition thereof.
All such shares shall upon their cancellation become authorized but unissued
shares of Preferred Stock and may be reissued as part of a new series of
Preferred Stock to be created by resolution or resolutions of the Board of
Directors, subject to the conditions and restrictions on issuance set forth
herein.

     Section 6.  Liquidation, Dissolution or Winding Up.  (A) Upon any
                 --------------------------------------               
liquidation (voluntary or otherwise), dissolution or winding up of the
Corporation, no distribution shall be made to the holders of shares of stock
ranking junior (either as to dividends or upon liquidation, dissolution or
winding up) to the Series A Junior Participating Preferred Stock unless, prior
thereto, the holders of shares of Series A Junior Participating Preferred Stock
shall have received $100 per share, plus an amount equal to accrued and unpaid
dividends and distributions thereon, whether or not declared, to the date of
such payment (the "Series A Liquidation Preference").  Following the payment of
the full amount of the Series A Liquidation Preference, no additional
distributions shall be made to the holders of shares of Series A Junior
Participating Preferred Stock unless, prior thereto, the holders of shares of
Common Stock shall have received an amount per share (the "Common Adjustment")
equal to the quotient obtained by dividing (i) the Series A Liquidation
Preference by (ii) 100 (as appropriately adjusted as set forth in subparagraph C
below to reflect such events as stock splits, stock dividends and
recapitalizations with respect to 
<PAGE>
 
the Common Stock) (such number in clause (ii), the "Adjustment Number").
Following the payment of the full amount of the Series A Liquidation Preference
and the Common Adjustment in respect of all outstanding shares of Series A
Junior Participating Preferred Stock and Common Stock, respectively, holders of
Series A Junior Participating Preferred Stock and holders of shares of Common
Stock shall receive their ratable and proportionate share of the remaining
assets to be distributed in the ratio of the Adjustment Number to 1 with respect
to such Preferred Stock and Common Stock, on a per share basis, respectively.

          (B) In the event, however, that there are not sufficient assets
available to permit payment in full of the Series A Liquidation Preference and
the liquidation preferences of all other series of Preferred Stock, if any,
which rank on a parity with the Series A Junior Participating Preferred Stock,
then such remaining assets shall be distributed ratably to the holders of such
parity shares in proportion to their respective liquidation preferences.  In the
event, however, that there are not sufficient assets available to permit payment
in full of the Common Adjustment, then such remaining assets shall be
distributed ratably to the holders of Common Stock.

          (C) In the event the Corporation shall at any time declare or pay any
dividend on Common Stock payable in shares of Common Stock, or effect a
subdivision, combination or consolidation of the outstanding Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the Adjustment Number in effect immediately prior to such event shall
be adjusted by multiplying such Adjustment Number by a fraction the numerator of
which is the number of shares of Common Stock outstanding immediately after such
event and the denominator of which is the number of shares of Common Stock that
were outstanding immediately prior to such event.

          (D) Neither the consolidation, merger or other business combination of
the Corporation with or into any other corporation nor the sale, lease, exchange
or conveyance of all or any part of the property, assets or business of the
Corporation shall be deemed to be a liquidation, dissolution or winding up of
the Corporation for purposes of this Section 6.

     Section 7.  Consolidation, Merger, etc.  In case the Corporation shall
                 --------------------------                                
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case the shares of
Series A Junior Participating Preferred Stock shall at the same time be
similarly exchanged or changed in an amount per share (subject to the provision
for adjustment hereinafter set forth) equal to 100 times the aggregate amount of
stock, securities, cash and/or any other property (payable in kind), as the case
may be, into which or for which each share of Common Stock is changed or
exchanged.  In the event the Corporation shall at any time declare or pay any
dividend on Common Stock payable in shares of Common Stock, or effect a
subdivision, combination or consolidation of the outstanding Common Stock (by
reclassification or otherwise than by payment of a dividend in shares of Common
Stock) into a greater or lesser number of shares of Common Stock, then in each
such case the amount set forth in the preceding sentence with respect to the
exchange or change of shares of Series A Junior 
<PAGE>
 
Participating Preferred Stock shall be adjusted by multiplying such amount by a
fraction the numerator of which is the number of shares of Common Stock
outstanding immediately after such event and the denominator of which is the
number of shares of Common Stock that were outstanding immediately prior to such
event.

     Section 8.  No Redemption.  The shares of Series A Junior Participating
                 -------------                                              
Preferred Stock shall not be redeemable.

     Section 9.  Ranking.  The Series A Junior Participating Preferred Stock
                 -------                                                    
shall rank junior to all other series of the Corporation's Preferred Stock as to
the payment of dividends and the distribution of assets, unless the terms of any
such series shall provide otherwise.

     Section 10.  Amendment.  The Certificate of Incorporation of the
                  ---------                                          
Corporation shall not be amended in any manner which would materially alter or
change the powers, preferences or special rights of the Series A Junior
Participating Preferred Stock so as to affect them adversely without the
affirmative vote of the holders of at least seventy-five percent of the
outstanding shares of Series A Junior Participating Preferred Stock, voting
together as a single class.

     Section 11.  Fractional Shares.  Series A Junior Participating Preferred
                  -----------------                                          
Stock may be issued in fractions of a share which shall entitle the holder, in
proportion to such holders fractional shares, to exercise voting rights, receive
dividends, participate in distributions and to have the benefit of all other
rights of holders of Series A Junior Participating Preferred Stock.



                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
<PAGE>
 
     IN WITNESS WHEREOF, said Cytyc Corporation has caused its corporate seal to
be hereunto affixed and this Certificate to be executed and attested, this _____
day of August 1997.

                                       CYTYC CORPORATION



                                       By:
                                          --------------------------------------
                                          Joseph W. Kelly
                                          Chief Financial Officer
<PAGE>
 
                                                                       EXHIBIT B
                                                                       ---------

                          [Form of Rights Certificate]


Certificate No. R-                                       Rights
                                              ----------


NOT EXERCISABLE AFTER SEPTEMBER 5, 2007 OR EARLIER IF REDEEMED BY THE COMPANY.
THE RIGHTS ARE SUBJECT TO REDEMPTION, AT THE OPTION OF THE COMPANY, AT $.01 PER
RIGHT ON THE TERMS SET FORTH IN THE RIGHTS AGREEMENT.  UNDER CERTAIN
CIRCUMSTANCES, RIGHTS BENEFICIALLY OWNED BY AN ACQUIRING PERSON, AN ADVERSE
PERSON OR AN AFFILIATE OR ASSOCIATE OF AN ACQUIRING PERSON OR AN ADVERSE PERSON
(AS SUCH TERMS ARE DEFINED IN THE RIGHTS AGREEMENT) AND ANY SUBSEQUENT HOLDER OF
SUCH RIGHTS MAY BECOME NULL AND VOID.  [THE RIGHTS REPRESENTED BY THIS RIGHTS
CERTIFICATE ARE OR WERE BENEFICIALLY OWNED BY A PERSON WHO WAS OR BECAME AN
ACQUIRING PERSON, AN ADVERSE PERSON OR AN AFFILIATE OR ASSOCIATE OF AN ACQUIRING
PERSON OR ADVERSE PERSON (AS SUCH TERMS ARE DEFINED IN THE RIGHTS AGREEMENT).
ACCORDINGLY, THIS RIGHTS CERTIFICATE AND THE RIGHTS REPRESENTED HEREBY MAY
BECOME NULL AND VOID IN THE CIRCUMSTANCES SPECIFIED IN SECTION 7(e) OF SUCH
AGREEMENT.]*




                               Rights Certificate

                               CYTYC CORPORATION


     This Rights Certificate certifies that _____________________, or registered
assigns, is the registered holder of the number of Rights set forth above, each
of which entitles the holder thereof, subject to the terms, provisions and
conditions of the Rights Agreement, dated as of August 27, 1997 (the "Rights
Agreement"), between Cytyc Corporation, a Delaware corporation (the "Company"),
and BankBoston, N.A. (the "Rights Agent"), to purchase from the Company after
the Distribution Date (as such term is defined in the Rights Agreement) and at
any time prior to the Expiration Date (as such term is defined in the Rights
Agreement) at the office or offices of the Rights Agent designated for such
purpose, or its successors as Rights Agent, one-hundredth of a fully paid, non-
assessable share of Series A Junior Participating Preferred Stock (the
"Preferred Stock") of the Company, at a purchase price of $110.00 per one one-
hundredth of a share (the "Purchase Price"), upon presentation and surrender of
this Rights Certificate with the Form of Election to Purchase and related
Certificate duly executed.  The number of Rights evidenced by this Rights
Certificate (and the number of shares which may be purchased upon exercise
thereof) set forth above, and the Purchase Price per share set forth above, are
the number and Purchase Price as of September 5, 1997 based on the Preferred
Stock as constituted at such date.  The Company reserves the right to require
prior to the occurrence of a Triggering Event (as such term is defined in the
Rights Agreement) that a number of Rights be exercised so that only whole shares
of Preferred Stock will be issued.
- --------------------------
* If applicable, insert this portion of the legend and delete preceding
sentence.
<PAGE>
 
     Capitalized terms used herein and not otherwise defined herein shall have
the meanings assigned to such terms in the Rights Agreement.


     Upon the occurrence of a Section 11(a)(ii) Event, if the Rights evidenced
by this Rights Certificate are beneficially owned by (i) an Acquiring Person, an
Adverse Person or an Affiliate or Associate of an Acquiring Person or Adverse
Person, (ii) a transferee of an Acquiring Person or an Adverse Person (or of any
such Associate or Affiliate of an Acquiring Person or an Adverse Person), or
(iii) under certain circumstances specified in the Rights Agreement, a
transferee of a person who, after such transfer, became an Acquiring Person or
an Adverse Person (or an Associate or Affiliate of an Acquiring Person or an
Adverse Person), such Rights shall become null and void and no holder hereof
shall have any right with respect to such Rights from and after the occurrence
of such Section 11(a)(ii) Event.

     As provided in the Rights Agreement, the Purchase Price and the number and
kind of shares of Preferred Stock or other securities which may be purchased
upon the exercise of the Rights evidenced by this Rights Certificate are subject
to modification and adjustment upon the happening of certain events, including
Triggering Events.

     This Rights Certificate is subject to all of the terms, provisions and
conditions of the Rights Agreement, which terms, provisions and conditions are
hereby incorporated herein by reference and made a part hereof and to which
Rights Agreement reference is hereby made for a full description of the rights,
limitations of rights, obligations, duties and immunities hereunder of the
Rights Agent, the Company and the holders of the Rights Certificates, which
limitations of rights include the temporary suspension of the exercisability of
such Rights under the specific circumstances set forth in the Rights Agreement.
Copies of the Rights Agreement are on file at the office of the Company and are
also available upon written request to the Company.

     This Rights Certificate, with or without other Rights Certificates, upon
surrender at the principal office or offices of the Rights Agent designated for
such purpose, may be exchanged for another Rights Certificate or Rights
Certificates of like tenor and date evidencing Rights entitling the holder to
purchase a like aggregate number of one one-hundredths of a share of Preferred
Stock as the Rights evidenced by the Rights Certificate or Rights Certificates
surrendered shall have entitled such holder to purchase.  If this Rights
Certificate shall be exercised in part, the holder shall be entitled to receive
upon surrender hereof another Rights Certificate or Rights Certificates for the
number of whole Rights not exercised.

     Subject to the provisions of the Rights Agreement, the Rights evidenced by
this Certificate may be redeemed by the Company at its option at a redemption
price of $.01 per Right at any time prior to the earlier of (i) the close of
business on the tenth day following the Stock Acquisition Date (or, if the Stock
Acquisition Date shall have occurred prior to the Record Date, the close of
business on the tenth day following the Record Date), and (ii) the Final
Expiration Date.  Under certain circumstances set forth in the Rights Agreement,
the decision to redeem shall require the concurrence of a majority of the
Continuing Directors.

     No fractional shares of Preferred Stock will be issued upon the exercise of
any Right or Rights evidenced hereby (other than fractions which are integral-
multiples of one one-hundredth of a share of Preferred Stock), but in lieu
thereof a cash payment will be made, as provided in the Rights Agreement.
<PAGE>
 
     No holder of this Rights Certificate shall be entitled to vote or receive
dividends or be deemed for any purpose the holder of shares of Preferred Stock
or of any other securities of the Company which may at any time be issuable on
the exercise hereof, nor shall anything contained in the Rights Agreement or
herein be construed to confer upon the holder hereof, as such, any of the rights
of a stockholder of the Company or any right to vote for the election of
directors or upon any matter submitted to stockholders at any meeting thereof,
or to give or withhold consent to any corporate action, or, to receive notice of
meetings or other actions affecting stockholders (except as provided in the
Rights Agreement), or to receive dividends or subscription rights, or otherwise,
until the Right or Rights evidenced by this Rights Certificate shall have been
exercised as provided in the Rights Agreement.

     This Rights Certificate shall not be valid or obligatory for any purpose
until it shall have been countersigned by the Rights Agent.

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal by its authorized officers.



Dated:

ATTEST:                                   CYTYC CORPORATION


 
                                                              
                                          By:
- ------------------------------               -----------------------------
Joseph W. Kelly                              Patrick J. Sullivan
Secretary                                    President and Chief
                                             Executive Officer

Countersigned:



By:
   -----------------------
   Authorized Signature
<PAGE>
 
                  [Form of Reverse Side of Rights Certificate]



 

                              FORM OF ASSIGNMENT
                              ------------------


                (To be executed by the registered holder if such
              holder desires to transfer the Rights Certificate.)


FOR VALUE RECEIVED _____________________________________________________________
hereby sells, assigns and transfers unto

________________________________________________________________________________

________________________________________________________________________________
                 (Please print name and address of transferee)

this Rights Certificate, together with all right, title and interest therein,
and does hereby irrevocably constitute and appoint __________ Attorney, to
transfer the within Rights Certificate on the books of the within-named Company,
with full power of substitution.


Dated:



                                                 -------------------------------
                                                 Signature

Signature Guaranteed:
<PAGE>
 
                                      -2-



                                  Certificate
                                  -----------


     The undersigned hereby certifies by checking the appropriate boxes that:

     (1)  this Rights Certificate [ ] is [ ] is not being sold, assigned and
transferred by or on behalf of a Person who is or was an Acquiring Person, an
Adverse Person or an Affiliate or Associate of an Acquiring Person or an Adverse
Person (as such terms are defined in the Rights Agreement);

     (2)  after due inquiry and to the best knowledge of the undersigned, it [ ]
did [ ] did not acquire the Rights evidenced by this Rights Certificate from any
Person who is, was or subsequently became an Acquiring Person, an Adverse Person
or an Affiliate or Associate of an Acquiring Person or an Adverse Person.


Dated:



                                               ---------------------------------
                                               Signature

Signature Guaranteed:





                                    NOTICE
                                    ------


     The signature to the foregoing Assignment and Certificate must correspond
to the name as written upon the face of this Rights Certificate in every
particular, without alteration or enlargement or any change whatsoever.
<PAGE>
 
                          FORM OF ELECTION TO PURCHASE
                          ----------------------------

                      (To be executed if holder desires to
                       exercise Rights represented by the
                              Rights Certificate.)


To:  CYTYC CORPORATION:

     The undersigned hereby irrevocably elects to exercise ______ Rights
represented by this Rights Certificate to purchase the shares of Preferred Stock
issuable upon the exercise of the Rights (or such other securities of the
Company or of any other person which may be issuable upon the exercise of the
Rights) and requests that certificates for such shares be issued in the name of
and delivered to:


Please insert social security
or other identifying number



- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------
                        (Please print name and address)


     If such number of Rights shall not be all the Rights evidenced by this
Rights Certificate, a new Rights Certificate for the balance of such Rights
shall be registered in the name of and delivered to:

Please insert social security
or other identifying number



- --------------------------------------------------------------------------------


- --------------------------------------------------------------------------------

                        (Please print name and address)

Dated:

                                               ---------------------------------
                                               Signature
Signature Guaranteed:
<PAGE>
 
                                  Certificate
                                  -----------


     The undersigned hereby certifies by checking the appropriate boxes that:

     (1)  the Rights evidenced by this Rights Certificate [ ] are [ ] are not
being exercised by or on behalf of a Person who is or was an Acquiring Person,
an Adverse Person or an Affiliate or Associate of an Acquiring Person or an
Adverse Person (as such terms are defined in the Rights Agreement);

     (2)  after due inquiry and to the best knowledge of the undersigned, it [ ]
did [ ] did not acquire the Rights evidenced by this Rights Certificate from any
Person who is, was or subsequently became an Acquiring Person, an Adverse Person
or an Affiliate or Associate of an Acquiring Person or an Adverse Person.


Dated:
                                                --------------------------------
                                                Signature


Signature Guaranteed:





                                    NOTICE
                                    ------

     The signature to the foregoing Election to Purchase and Certificate must
correspond to the name as written upon the face of this Rights Certificate in
every particular, without alteration or enlargement or any change whatsoever.
<PAGE>
 
                                                                       EXHIBIT C
                                                                       ---------

                 SUMMARY OF RIGHTS TO PURCHASE PREFERRED STOCK


          On August 6, 1997, the Board of Directors of Cytyc Corporation (the
"Company") declared a dividend of one preferred stock purchase right (a "Right")
- --------                                                                 -----  
for each outstanding share of the Company's Common Stock to stockholders of
record at the close of business on September 5, 1997 (the "Record Date").  Each
                                                           -----------         
Right entitles the registered holder to purchase from the Company a unit
consisting of one one-hundredth of a share (a "Unit") of Series A Junior
                                               ----                     
Participating Preferred Stock, $.01 par value per share (the "Preferred Stock"),
                                                              ---------------   
at a purchase price of $110 per Unit (the "Purchase Price"), subject to
                                           --------------              
adjustment.  The description and terms of the Rights are set forth in a Rights
Agreement (the "Rights Agreement") between the Company and BankBoston, N.A., as
                ----------------                                               
Rights Agent.

          Initially, the Rights will be attached to all Common Stock
certificates representing shares then outstanding, and no separate Rights
Certificates will be distributed.  The Rights will separate from the Common
Stock and a Distribution Date will occur upon the earliest of (i) the close of
business on the tenth day (or such later date as may be determined by action of
the Board (with the concurrence of the majority of the Continuing Directors (as
defined below))) following a public announcement that a person or group of
affiliated or associated persons (an "Acquiring Person") has acquired, or
                                      ----------------                   
obtained the right to acquire, beneficial ownership of 15% or more of the
outstanding shares of Common Stock (the "Stock Acquisition Date"), (ii) the
                                         ----------------------            
close of business on the tenth business day (or such later date as may be
determined by action of the Board (with the concurrence of the majority of the
Continuing Directors)) following the commencement of a tender offer or exchange
offer that may result in a person or group beneficially owning 15% or more of
such outstanding shares of Common Stock or (iii) the close of business on the
tenth business day after the Continuing Directors (with the concurrence of the
Independent Directors) of the Company shall declare any Person to be an Adverse
Person, upon a determination that such Person, alone or together with its
affiliates and associates, has become the Beneficial Owner of an amount of
Common Stock which the Continuing Directors determine to be substantial (which
amount shall in no event be less than 10% of the shares of Common Stock then
outstanding) and a majority of the Continuing Directors (with the concurrence of
a majority of the Independent Directors (as defined below)) determines, after
reasonable inquiry and investigation, including consultation with such persons
as such directors shall deem appropriate, that (a) such beneficial ownership by
such person is intended to cause the Company to repurchase the Common Stock
beneficially owned by such person or to cause pressure on the Company to take
action or enter into a transaction or series of transactions intended to provide
such person with short-term financial gain under circumstances where such
directors determine that the best long-term interests of the Company and its
stockholders would not be served by taking such action or entering into such
transaction or series of transactions at that time or (b) such beneficial
ownership is causing or is reasonably likely to cause a material adverse impact
(including, but not limited to, impairment of relationships with customers,
impairment of the Company's ability to maintain its competitive position or
impairment of the Company's business 


<PAGE>

reputation or ability to deal with government agencies) on the business or
prospects of the Company.

          Until the Distribution Date (or earlier redemption or expiration of
the Rights), (i) the Rights will be evidenced by the Common Stock certificates
and will be transferred with and only with such Common Stock certificates, (ii)
new Common Stock certificates issued after the Record Date will contain a legend
incorporating the Rights Agreement by reference and (iii) the surrender for
transfer of any certificates for Common Stock outstanding, even without such
legend, will also constitute the transfer of the Rights associated with the
Common Stock represented by such certificate.  Pursuant to the Rights Agreement,
the Company reserves the right to require prior to the occurrence of a
Triggering Event (as defined below) that, upon any exercise of Rights, a number
of Rights may be exercised so that only whole shares of Preferred Stock will be
issued.

          The Rights are not exercisable until the Distribution Date and will
expire at the close of business on September 5, 2007,  unless earlier redeemed
by the Company as described below.

          As soon as practicable after the Distribution Date, separate
certificates evidencing the Rights ("Rights Certificates") will be mailed to
                                     -------------------                    
holders of record of the Common Stock as of the close of business on the
Distribution Date and, thereafter, such separate Rights Certificates alone will
represent the Rights.  Except as otherwise determined by the Board of Directors
and except in connection with shares of Common Stock issued upon the exercise of
employee stock options, issuances under other employee stock benefit plans or
upon the conversion of convertible securities issued hereafter, only shares of
Common Stock issued prior to the Distribution Date will be issued with Rights.

          In the event that the Continuing Directors determine that a person is
an Adverse Person or, at any time following the Distribution Date, (i) the
Company is the surviving corporation in a merger with an Acquiring Person and
its Common Stock is not changed or exchanged, (ii) a Person becomes the
beneficial owner of 20% or more of the then outstanding shares of Common Stock
(except pursuant to an offer for all outstanding shares of Common Stock which a
majority of the Independent Directors determine to be fair to, and otherwise in
the best interests of, the Company and its stockholders), (iii) an Acquiring
Person engages in one or more "self-dealing" transactions as set forth in the
Rights Agreement, or (iv) during such time as there is an Acquiring Person, an
event occurs which results in such Acquiring Person's ownership interest being
increased by more than 1% (e.g., a reverse stock split), each holder of a Right
will thereafter have the right to receive, upon exercise, that number of shares
of Common Stock (or, in certain circumstances, cash, property or other
securities of the Company) which equals the exercise price of the Right divided
by one-half of the current market price (as defined in the Rights Agreement) of
the Common Stock at the date of the occurrence of the event.  However, Rights
are not exercisable following the occurrence of any of the events set forth
above until such time as the Rights are no longer redeemable by the Company as
set forth below.  Notwithstanding any of the foregoing, following the occurrence
of any of 



<PAGE>

 
the events set forth in this paragraph, all Rights that are, or (under certain
circumstances specified in the Rights Agreement were, beneficially owned by an
Acquiring Person or an Adverse Person will be null and void. The events set
forth in this paragraph are described in Section 11(a)(ii) of the Rights
Agreement and are referred to as "Section 11(a)(ii) Events."

          In the event that, at any time following the Stock Acquisition Date,
(i) the Company is acquired in a merger or other business combination
transaction in which the Company is not the surviving corporation (other than a
merger which follows an offer determined by the Board of Directors to be fair as
described in clause (ii) of the second preceding paragraph), or (ii) more than
50% of the Company's assets or earning power is sold or transferred, each holder
of a Right (except Rights which previously have been voided as set forth above)
shall thereafter have the right to receive, upon exercise, that number of shares
of common stock of the acquiring company which equals the exercise price of the
Right divided by one-half of the current market price (as defined in the Rights
Agreement) of such common stock at the date of the occurrence of the event.  The
events set forth in this paragraph and in the preceding paragraph are referred
to as the "Triggering Events."
           -----------------  

          At any time after the occurrence of a Section 11(a)(ii) Event, the
Board (with the concurrence of a majority of the Continuing Directors) may
exchange the Rights (other than Rights owned by an Acquiring Person or Adverse
Person which have become void), in whole or in part, at an exchange ratio of one
share of Common Stock, or one Common Stock Equivalent (as defined in the Rights
Agreement), per Right (subject to adjustment).

          The Purchase Price payable, and the number of Units of Preferred Stock
or other securities or property issuable, upon exercise of the Rights are
subject to adjustment from time to time to prevent dilution (i) in the event of
a stock dividend on, or a subdivision, combination or reclassification of, the
Preferred Stock, (ii) if holders of the Preferred Stock are granted certain
rights or warrants to subscribe for Preferred Stock or convertible securities at
less than the current market price of the Preferred Stock, or (iii) upon the
distribution to holders of the Preferred Stock of evidences of indebtedness or
assets (excluding regular quarterly cash dividends) or of subscription rights or
warrants (other than those referred to above).

          With certain exceptions, no adjustment in the Purchase Price will be
required until cumulative adjustments amount to at least 1% of the Purchase
Price.  No fractional Units will be issued and, in lieu thereof, an adjustment
in cash will be made based on the market price of the Preferred Stock on the
last trading date prior to the date of exercise.

          In general, the Company may redeem the Rights in whole, but not in
part, at any time until ten days following the Stock Acquisition Date, at a
price of $.01 per Right (payable in cash, Common Stock or other consideration
deemed appropriate by the Board of Directors).  Under certain circumstances set
forth in the Rights Agreement, the decision to redeem shall require the
concurrence of a majority of the Continuing 



<PAGE>

Directors. The Company may not redeem the Rights if the Continuing Directors
have previously declared a person to be an Adverse Person. Immediately upon the
action of the Board of Directors ordering redemption of the Rights, with, where
required, the concurrence of the Continuing Directors, the Rights will terminate
and the only right of the holders of Rights will be to receive the $.01 per
Right redemption price.

          The term "Continuing Directors" means any member of the Board of
                    --------------------                                  
Directors of the Company who was a member of the Board of directors on the date
of the Rights Agreement, and any person who is subsequently elected to the Board
of Directors if such person is recommended or approved by a majority of the
Continuing Directors, but shall not include an Acquiring Person, an Adverse
Person or an affiliate or associate of an Acquiring Person or an Adverse Person,
or any representative of the foregoing entities.  The term "Independent
                                                            -----------
Directors" means Continuing Directors who are not officers of the Company.
- ---------                                                                 

          Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the Company, including, without limitation, the right
to vote or to receive dividends.  While the distribution of the Rights will not
be taxable to stockholders or to the Company, stockholders may, depending upon
the circumstances, recognize taxable income in the event that the Rights become
exercisable for Common Stock (or other consideration) of the Company or for
common stock of the acquiring company as set forth above.

          The provisions of the Rights Agreement may be amended by the Board of
Directors of the Company prior to the earlier to occur of the determination that
a person is an Adverse Person or the Distribution Date.  After the earlier of
such events, the provisions of the Rights Agreement may be amended by the Board
of Directors (in certain circumstances, with the concurrence of the Continuing
Directors) in order to cure any ambiguity, to make changes which do not
adversely affect the interests of holders of Rights (excluding the interests of
any Acquiring Person or any Adverse Person), or to shorten or lengthen any time
period under the Rights Agreement; provided, however, that no amendment to
                                   --------  -------                      
adjust the time period governing redemption shall be made at such time as the
Rights are not redeemable.

     A copy of the Rights Agreement is available free of charge from the
Company. This summary description of the Rights does not purport to be complete
and is qualified in its entirety by reference to the Rights Agreement, which is
incorporated herein by reference.


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