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                    SECURITIES AND EXCHANGE COMMISSION
                         Washington, D.C. 20549
        
                    ----------------------------------

                     RULE 13E-3 TRANSACTION STATEMENT
        (Pursuant to Section 13(e) of the Securities Exchange Act of 1934)

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

                          MYCOGEN CORPORATION
                          (Name of the Issuer)

                        THE DOW CHEMICAL COMPANY
                          ROFAN SERVICES INC.
                            CENTEN AG INC.
                          DOW AGROSCIENCES LLC
                                 and
                     AGROSCIENCES ACQUISITION INC.
                 (Name of Person(s) Filing Statement)

                             COMMON STOCK
                      PAR VALUE $0.001 PER SHARE
       (INCLUDING THE ASSOCIATED PREFERRED STOCK PURCHASE RIGHTS)
                    (Title of Class of Securities)

                             628452 10 4
                (CUSIP Number of Class of Securities)

       John Scriven              Jane M. Gootee         Brian G. Taylorson
  Vice President, General        Vice President              President
   Counsel and Secretary       Rofan Services Inc.         Centen Ag Inc.
  The Dow Chemical Company       2030 Dow Center          2030 Dow Center
      2030 Dow Center        Midland, Michigan 48674  Midland, Michigan 48674
  Midland, Michigan 48674         (517) 636-1000           (517) 636-1000
       (517) 636-1000

                 Louis W. Pribila             Brian G. Taylorson
            Vice President, Secretary              President
               and General Counsel         AgroSciences Acquisition Inc.
              Dow AgroSciences LLC               2030 Dow Center
              9330 Zionsville Road           Midland, Michigan 48674
           Indianapolis, Indiana 46268           (517) 636-1000
                 (317) 337-3000

                                 with a copy to:

                                 Scott J. Davis
                                James T. Lidbury
                              Mayer, Brown & Platt
                            190 South LaSalle Street
                             Chicago, Illinois 60603
                                 (312) 782-0600
             (Name, Address and Telephone Number of Person Authorized to 
     Receive Notices and Communications on Behalf of Persons Filing Statement)

This statement is filed in connection with (check the appropriate box):
     a.   / /  The filing of solicitation materials or an information statement
               subject to Regulation 14A, Regulation 14C or Rule 13e-3(c) under
               the Securities Act of 1934.
     b.   / /  The filing of a registration statement under the Securities Act
               of 1933.
     c.   /X/  A tender offer.
     d.   / /  None of the above.
Check the following box if the soliciting materials or information statement
referred to in checking box (a) are preliminary copies:  / /
                              CALCULATION OF FILING FEE

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Transaction Valuation*                   Amount of Filing Fee
                                            
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$374,232,918                                    $74,847
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*    For purposes of calculating the filing fee only.  This amount assumes the
     purchase of 11,532,381 shares of common stock (the "Shares") of the subject
     company at $28.00 in cash per Share as well as the purchase of 3,568,635
     Shares subject to outstanding options at $28.00 per Share less the
     average exercise price per Share subject to such options of $13.6174.
     Check box if any part of the fee is offset as provided by Rule 0-11(a)(2)
     and identify the filing with which the offsetting fee was previously paid.
     Identify the previous filing by registration statement number, or the Form
     or Schedule and the date of its filing.

/X/  Amount Previously Paid:       $74,847
     Form or Registration Number:  Schedule 14D-1.
     Filing Party:                 The Dow Chemical Company, Rofan Services 
                                   Inc., Centen Ag Inc., Dow AgroSciences LLC
                                   and AgroSciences Acquisition Inc.
     Date Filed:                   September 4, 1998.
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                           INTRODUCTION

     This Rule 13e-3 Transaction Statement (the "Statement") is being filed 
by The Dow Chemical Company ("TDCC"), Rofan Services Inc. ("Rofan"), Centen 
Ag Inc. ("Centen"), AgroSciences Acquisition Inc. ("Purchaser") and Dow 
AgroSciences LLC ("Parent").  Rofan and Centen are wholly owned subsidiaries 
of TDCC, a public corporation whose stock is traded on the NYSE.  Rofan and 
Centen own 63% and 37%, respectively, of the interests of Parent.  Parent 
owns 69% of the common stock of Purchaser, and Centen owns the remaining 31% 
of the common stock of Purchaser.  Parent holds approximately 68.3% of the 
outstanding shares of common stock, par value $0.001 per share (the 
"Shares"), of Mycogen Corporation (the "Company").  This Statement relates to 
a proposed merger (the "Merger") in which Purchaser would merge with and into 
the Company and the Shares other than those Shares held by Parent or 
Purchaser would be converted into the right to receive $28.00 per Share in 
cash.

     The following cross reference sheet is being supplied pursuant to 
General Instruction F to the Statement and shows the location in the Offer to 
Purchase dated September 4, 1998 (the "Offer to Purchase") filed as 
Exhibit 99(d)(1) hereto by the Purchaser with the Securities and Exchange 
Commission on the date hereof, of the information required to be included 
in response to the items of this Statement. The information set forth in the 
Offer to Purchase, which is attached hereto as Exhibit 99(d)(1), is hereby 
expressly incorporated herein by reference and the responses to each item 
are qualified in their entirety by the provisions of the Offer to Purchase. 

                                     -1-

 

                             CROSS REFERENCE SHEET




ITEM IN SCHEDULE 13E-3                          WHERE LOCATED IN SCHEDULE 14D-1
- ----------------------                          -------------------------------
                                             

Item 1(a)-(c) . . . . . . . . . . . . . . . .   Item 1(a)-(c)
Item 1(d)-(f) . . . . . . . . . . . . . . . .   *
Item 2. . . . . . . . . . . . . . . . . . . .   Item 2
Item 3(a)(1). . . . . . . . . . . . . . . . .   Item 3(a)(1)
Item 3(a)(2). . . . . . . . . . . . . . . . .   Item 3(b)
Item 3(b) . . . . . . . . . . . . . . . . . .   *
Item 4. . . . . . . . . . . . . . . . . . . .   *
Item 5(a)-(e) . . . . . . . . . . . . . . . .   Item 5(a)-(e)
Item 5(f) . . . . . . . . . . . . . . . . . .   Item 5(g)
Item 5(g) . . . . . . . . . . . . . . . . . .   *
Item 6(a) . . . . . . . . . . . . . . . . . .   Item 4(a)
Item 6(b) . . . . . . . . . . . . . . . . . .   *
Item 6(c)-(d) . . . . . . . . . . . . . . . .   Item 4(b)-(c)
Item 7(a) . . . . . . . . . . . . . . . . . .   Item 5
Item 7(b)-(d) . . . . . . . . . . . . . . . .   *
Item 8. . . . . . . . . . . . . . . . . . . .   *
Item 9. . . . . . . . . . . . . . . . . . . .   *
Item 10 . . . . . . . . . . . . . . . . . . .   Item 6
Item 11 . . . . . . . . . . . . . . . . . . .   Item 7
Item 12 . . . . . . . . . . . . . . . . . . .   *
Item 13 . . . . . . . . . . . . . . . . . . .   *
Item 14 . . . . . . . . . . . . . . . . . . .   *
Item 15(a). . . . . . . . . . . . . . . . . .   *
Item 15(b). . . . . . . . . . . . . . . . . .   Item 8
Item 16 . . . . . . . . . . . . . . . . . . .   Schedule 14D-1
Item 17(a). . . . . . . . . . . . . . . . . .   Item 11(b)
Item 17(b). . . . . . . . . . . . . . . . . .   *
Item 17(c). . . . . . . . . . . . . . . . . .   Item 11(c)
Item 17(d). . . . . . . . . . . . . . . . . .   *
Item 17(e). . . . . . . . . . . . . . . . . .   *
Item 17(f). . . . . . . . . . . . . . . . . .   Not Applicable

- -----------------
*     This information is provided only in this Schedule 13E-3.

                               -2-



ITEM 1.       ISSUER AND CLASS OF SECURITY SUBJECT TO THE TRANSACTION.

     (a)      The name of the subject company is Mycogen Corporation, a 
corporation organized under the laws of California (the "Company"), which has 
its principal executive offices at 5501 Oberlin Drive, San Diego, California 
92121. Capitalized terms used in this Schedule 13E-3 and not defined herein 
shall have the meanings set forth in the Offer to Purchase dated September 4, 
1998 (the "Offer to Purchase") attached hereto as Exhibit 99(d)(1).

     (b)      The information set forth in the "Introduction" of the Offer to 
Purchase is incorporated herein by reference.

     (c)-(d) and (f) The information set forth in "The Tender Offer - 6. 
Price Range of the Shares" of the Offer to Purchase is incorporated herein by 
reference.

     (e)      Not Applicable.


ITEM 2.       IDENTITY AND BACKGROUND.

     (a)-(d) and (g)  The information set forth in "Introduction," "The 
Tender Offer - 8. Certain Information Concerning Purchaser, Parent and 
Certain Affiliates of Parent" and Schedule I of the Offer to Purchase is 
incorporated herein by reference.

     (e)-(f)   During the last five years, neither The Dow Chemical Company, 
a Delaware corporation, nor Rofan Services Inc., a Delaware corporation, nor 
Centen Ag Inc., a Delaware corporation, nor Dow AgroSciences LLC, a Delaware 
limited liability company ("Parent"), nor AgroSciences Acquisition Inc., a 
Delaware corporation ("Purchaser") and a majority-owned subsidiary of Parent, 
nor, to the best of their  knowledge, any of the individuals listed in "The 
Tender Offer - 8. Certain Information Concerning Purchaser, Parent and 
Certain Affiliates of Parent" or in Schedule I of the Offer to Purchase has 
(i) been convicted in a criminal proceeding (excluding traffic violations or 
similar misdemeanors) or (ii) been a party to a civil proceeding of a 
judicial or administrative body of competent jurisdiction and, as a result of 
such proceeding, was or is subject to a judgment, decree or final order 
enjoining future violations of, or prohibiting activities subject to, federal 
or state securities laws or finding any violation of such laws.

ITEM 3.       PAST CONTACTS, TRANSACTIONS OR NEGOTIATIONS.

     (a)      The information set forth in "The Tender Offer - 8. Certain 
Information Concerning Purchaser, Parent and Certain Affiliates of Parent" 
and "The Tender Offer - 9. Background of the Offer" of the Offer to Purchase 
is incorporated herein by reference.

     (b)      The information set forth in "The Tender Offer -- 9. Background 
of the Offer" of the Offer to Purchase is incorporated herein by reference.

ITEM 4.       TERMS OF THE TRANSACTION.

     The information set forth in "Introduction" and "The Tender Offer -- 10. 
 Purpose of the Offer; The Merger Agreement" of the Offer to Purchase is 
incorporated herein by reference.

ITEM 5.       PLANS OR PROPOSALS OF THE ISSUER OR AFFILIATE.

     The information set forth in "The Tender Offer--9. Background of the 
Offer," "The Tender Offer--10. Purpose of the Offer; The Merger Agreement" 
and "The Tender Offer -- 12. Certain Effects of the Offer; Exchange Act 
Registration; Filing Requirements" of the Offer to Purchase is incorporated 
herein by reference.

ITEM 6.       SOURCE AND AMOUNTS OF FUNDS OR OTHER CONSIDERATION.

     (a)      The information set forth in "The Tender Offer - 11. Source and 
Amount of Funds" of the Offer to Purchase is incorporated herein by reference.

     (b)      The information set forth in "The Tender Offer -- 16. Fees and 
Expenses" of the Offer to Purchase is incorporated herein by reference.

                                  -3-



     (c)-(d)  None.

ITEM 7.       PURPOSE(S), ALTERNATIVES, REASONS AND EFFECTS.

     The information set forth in "The Tender Offer -- 5. Certain Tax 
Consequences," "The Tender Offer -- 9. Background of the Offer," "The Tender 
Offer -- 10.   Purpose of the Offer; The Merger Agreement" and "The Tender 
Offer -- 12. Certain Effects of the Offer" of the Offer to Purchase is 
incorporated herein by reference.

ITEM 8.       FAIRNESS OF THE TRANSACTION.

     (a)-(b) and (d)-(e)   The information set forth in "Recommendation of the
Company's Board of Directors" and "The Tender Offer -- 9.  Background of the
Offer" of the Offer to Purchase is incorporated herein by reference.

     (c)      The Merger is structured to require the approval of at least a 
majority of the unaffiliated security holders.

     (f)      Not Applicable.

ITEM 9.       REPORTS, OPINIONS, APPRAISALS AND CERTAIN NEGOTIATIONS.

     The information set forth in "Recommendation of the Company's Board of 
Directors," "The Tender Offer  --  9. Background of the Offer" and "The 
Tender Offer -- 16.  Fees and Expenses" of the Offer to Purchase is 
incorporated herein by reference.

ITEM 10.      INTEREST IN SECURITIES OF THE ISSUER.


                                      SHARES
                                            BENEFICIALLY   PERCENTAGE
          NAME                                 OWNED       OF CLASS  
          -----------------------           -------------  -----------
                                                     
(a)-(b)   The Dow Chemical Company           24,766,157      68.3%
          2030 Dow Center                   
          Midland, MI 48674                 
          (517) 636-1000                    
                                            
          Rofan Services, Inc.               24,766,157      68.3%
          2030 Dow Center                   
          Midland, MI 48674                 
          (517) 636-1000                    
                                            
          Centen Ag Inc.                              0         0%
          2030 Dow Center                                
          Midland, MI 48674                              
          (517) 636-1000                                 
                                            
          Dow AgroSciences LLC               24,766,157      68.3%
          9330 Zionsville Road              
          Indianapolis, IN 46268            
          (317) 337-3000                    
                                            
          AgroSciences Acquisition Inc.               0         0%
          2030 Dow Center
          Midland, MI 48674
          (517) 636-1000


     The information set forth in "The Tender Offer--6. Price Range of the 
Shares" and "The Tender Offer--8. Certain Information Concerning Purchaser, 
Parent and Certain Affiliates of Parent" of the Offer to Purchase is 
incorporated herein by reference.

ITEM 11.      CONTRACTS, ARRANGEMENTS OR UNDERSTANDINGS WITH RESPECT TO THE
              ISSUER'S SECURITIES.

     The information set forth in "The Tender Offer - 8. Certain Information 
Concerning Purchaser, Parent and Certain Affiliates of Parent," "The Tender 
Offer--9. Background of the Offer" and "The Tender Offer - 10. Purpose of the 
Offer; Merger Agreement" of the Offer to Purchase is incorporated herein by 
reference.

ITEM 12.      PRESENT INTENTION AND RECOMMENDATION OF CERTAIN PERSONS WITH 
              REGARD TO THE TRANSACTION.

     (a)      The information set forth in "The Tender Offer--8. Certain 
Information Concerning Purchaser, Parent and Certain Affiliates of Parent" of 
the Offer to Purchase is incorporated herein by reference.

     (b)      The information set forth in "The Tender Offer--9. Background 
of the Offer" of the Offer to Purchase is incorporated herein by reference.


                                     -4-



ITEM 13.      OTHER PROVISIONS OF THE TRANSACTION.

     (a)      The information set forth in "The Tender Offer -- 10. Purpose 
of the Offer; The Merger Agreement" is incorporated herein by reference.

     (b)      Not applicable.

     (c)      Not applicable.
     

                                      -5-



ITEM 14.      FINANCIAL INFORMATION.

     The information set forth in "The Tender Offer -- 7.  Certain 
Information Concerning the Company"  and "The Tender Offer--8. Certain 
Information Concerning Purchaser, Parent and Certain Affiliates of Parent" of 
the Offer to Purchase and the Company's Annual Report on Form 10-K for the 
year ended August 31, 1997, and the Company's Quarterly Reports on Form 10-Q 
for the quarters ended November 30, 1997, February 28, 1998, and May 31, 
1998, is incorporated herein by reference.

ITEM 15.      PERSONS AND ASSETS EMPLOYED, RETAINED OR UTILIZED.

     (a)      The information set forth in "The Tender Offer -- 10. Purpose 
of the Offer; Merger Agreement" of the Offer to Purchase is incorporated 
herein by reference.

     (b)      The information set forth in "The Tender Offer -- 16. Fees and 
Expenses" of the Offer to Purchase is incorporated herein by reference.

ITEM 16.      ADDITIONAL INFORMATION.

     Reference is hereby made to the Offer to Purchase and the related Letter 
of Transmittal, copies of which are attached hereto as Exhibits 99(d)(1) and 
99(d)(2), respectively, and which are incorporated herein in their entirety 
by reference.



ITEM 17.            MATERIAL TO BE FILED AS EXHIBITS.
                 
(a) and (f) . . .   Not Applicable.
(b)-(e) . . . . .   A list of exhibits filed with this Schedule 13E-3
                    is set forth on the Exhibit Index immediately 
                    following the signature page of this Schedule 13E-3 
                    and is incorporated herein by reference.


                                   -6-


                                SIGNATURES


     After due inquiry and to the best of my knowledge and belief, I certify 
that the information set forth in this statement is true, complete and 
correct.

Dated:  September 4, 1998.    THE DOW CHEMICAL COMPANY


                              By /s/ G. MICHAEL LYNCH
                                 --------------------------------------
                                 Name:  G. Michael Lynch
                                 Title: Vice President and Controller


                              ROFAN SERVICES INC.


                              By /s/ J. PEDRO REINHARD
                                 --------------------------------------
                                 Name: J. Pedro Reinhard
                                 Title: President


                              CENTEN AG INC.


                              By /s/ BRIAN G. TAYLORSON
                                 --------------------------------------
                                 Name: Brian G. Taylorson
                                 Title: President


                              DOW AGROSCIENCES LLC


                              By /s/ LOUIS W. PRIBILA
                                 --------------------------------------
                                 Name: Louis W. Pribila
                                 Title: Vice President, Secretary and
                                        General Counsel


                              AGROSCIENCES ACQUISITION INC.


                              By /s/ BRIAN G. TAYLORSON
                                 --------------------------------------
                                 Name: Brian G. Taylorson
                                 Title: President

                                 -7-



                                 EXHIBIT INDEX


                                                                                  SEQUENTIALLY
  EXHIBIT NO.                   DESCRIPTION                                       NUMBERED PAGE
 ------------                   -----------                                      ---------------
                                                                           
  99(b)(1)          Salomon Smith Barney Report to Dow AgroSciences LLC 
                    dated August 3, 1998.                                        
  99(b)(2)          Wasserstein Perella & Co., Inc. Report to the Special 
                    Committee of Mycogen Corporation dated August 3, 1998.       
  99(b)(3)          Wasserstein Perella & Co., Inc. Report to the Special 
                    Committee of Mycogen Corporation dated August 31, 1998.      
  99(b)(4)          Opinion of Wasserstein Perella & Co., Inc. to the Special 
                    Committee of Mycogen Corporation dated August 31, 1998 
                    (Incorporated herein by reference from Schedule III to the 
                    Offer to Purchase).                                          
  99(c)(1)          Agreement and Plan of Merger among Mycogen Corporation, 
                    Dow AgroSciences LLC and AgroSciences Acquisition Inc. 
                    dated as of August 31, 1998. (Incorporated herein by 
                    reference from Exhibit 99.1 to Amendment No. 15 to 
                    Schedule 13D filed September 1, 1998).                       
  99(c)(2)          Confidentiality Agreement among Mycogen Corporation, The 
                    Dow Chemical Company and Dow AgroSciences LLC dated July 
                    16, 1998.                                                    
  99(c)(3)          Exchange and Purchase Agreement among Mycogen 
                    Corporation, Agrigenetics, Inc., DowElanco and United 
                    AgriSeeds, Inc. dated as of January 15, 1996 
                    (Incorporated herein by reference from Exhibit 99(a)(1) 
                    to Schedule 13D filed January 25, 1996).                     
  99(c)(4)          Amendment to Exchange and Purchase Agreement between 
                    Mycogen Corporation and Dow AgroSciences LLC dated as of 
                    July 22, 1998 (Incorporated herein by reference from 
                    Exhibit 99(1) to Amendment No. 14 to Schedule 13D filed 
                    July 23, 1998).                                              
  99(c)(5)          Technology Agreement among Mycogen Corporation, 
                    Agrigenetics, Inc. and DowElanco dated as of February 
                    19, 1996 (Incorporated herein by reference from Exhibit B 
                    to Exhibit 99(a)(1) to Schedule 13D filed January 25, 
                    1996).                                                       
  99(c)(6)          Brassica License and Research Agreement between Dow 
                    Elanco Canada and Mycogen Corporation dated October 30, 
                    1997.                                                        
  99(c)(7)          Restated Loan Agreement between Dow AgroSciences LLC and 
                    Mycoyen S.A. dated May 15, 1998.                             
  99(c)(8)          Loan Agreement between Dow Elanco and Mycogen Corporation 
                    dated as of April 1, 1997 (the "Dow Loan Agreement").        
  99(c)(9)          Amendment No. 1 to Dow Loan Agreement dated as of 
                    September 29, 1997.                                          
  99(c)(10)         Amendment No. 2 to Dow Loan Agreement dated as of 
                    November 14, 1997.                                           
  99(c)(11)         Amendment No. 3 to Dow Loan Agreement dated as of 
                    November 18, 1997.                                           
  99(c)(12)         Amendment No. 4 to Dow Loan Agreement dated as of April 
                    6, 1998.                                                     
  99(c)(13)         Amendment No. 5 to Dow Loan Agreement dated as of October 
                    1, 1997.                                                     
  99(c)(14)         Loan Agreement between Mycogen Corporation and DowElanco 
                    dated as of April 1, 1997 (the "Mycogen Loan Agreement").    
  99(c)(15)         Amendment No. 1 to Mycogen Loan Agreement dated as of 
                    April 6, 1998.                                               
  99(c)(16)         Amendment No. 2 to Mycogen Loan Agreement dated as of 
                    October 1, 1997.                                             
  99(c)(17)         Memorandum of Understanding dated September 3, 1998.         
  99(d)(1)          Offer to Purchase dated September 4,
                    1998.                                                        
  99(d)(2)          Form of Letter of Transmittal.                               
  99(d)(3)          Form of Notice of Guaranteed Delivery.                       
  99(d)(4)          Form of Letter to Brokers, Dealers,
                    Commercial Banks, Trust Companies and
                    other Nominees dated September 4, 1998.                      
  99(d)(5)          Form of Letter to Clients for use by
                    Brokers, Dealers, Commercial Banks,
                    Trust Companies and other Nominees.                          
  99(d)(6)          Form of Option Election.                                     
  99(d)(7)          Form of Stock Purchase Election.                             
  99(d)(8)          Form of Restricted Stock Election.                           
  99(d)(9)          Guidelines for Certification of
                    Taxpayer Identification Number on
                    Substitute Form W-9.                                         
  99(d)(10)         Form of Summary Advertisement.                               
  99(e)(1)          Chapter 13 of the California General Corporation Law 
                    (Incorporated herein by reference from Schedule II to
                    the Offer to Purchase).                                      
  99(g)(1)          Complaint filed in Susser v. Mycogen Corporation et al. 
                    (Superior Court of the State of California, County of San 
                    Diego, filed May 1, 1998).                                   
  99(g)(2)          Complaint filed in Harbor Finance Partners v. Mycogen 
                    Corporation et al. (Superior Court of the State of 
                    California, County of San Diego, filed May 1, 1998).         
  99(g)(3)          Complaint filed in Ellis Investments, Ltd. v.  
                    Eibl et al. (Superior Court of the State of California, 
                    County of San Diego, filed May 1, 1998).                     
  99(g)(4)          Complaint filed in Kolb v. Mycogen Corporation et al. 
                    (Superior Court of the State of California, County of San 
                    Deigo, filed May 5, 1998).                                   
  99(g)(5)          Complaint filed in Anderson v. Mycogen Corporation et al.
                    (Superior Court of the State of California, County of 
                    San Diego, filed May 5, 1998).                               
  99(g)(6)          Complaint filed in Boettcher v. Mycogen Corporation et al. 
                    (Superior Court of the State of California, County of San 
                    Diego, filed May 8, 1998).                                   
  99(g)(7)          Complaint filed in Verrone v. Mycogen Corporation et al. 
                    (Superior Court of the State of California, County of San 
                    Diego, filed May 15, 1998).                                  
  99(g)(8)          Order of Consolidation entered in Susser v. Mycogen 
                    Corporation et al. (Superior Court of State of 
                    California, County of San Diego, entered June 22, 1998).