EXHIBIT 2.2

                                February 2, 1999

Midwest Bancshares, Inc.
3225 Division Street
Burlington, IA 52601

Ladies and Gentlemen:

    This letter is intended to  supplement  the  Agreement and Plan of Merger by
and between Mahaska Investment Company ("Mahaska") and Midwest Bancshares,  Inc.
("Company")  dated of even date herewith (the "Merger  Agreement")  and sets out
the agreements of the parties  relating to various issues not fully addressed in
the  Merger  Agreement.  The  provisions  of this  letter  agreement  are hereby
incorporated into and made part of Section 4.18(c) of the Merger Agreement as if
set  forth  therein.  Capitalized  terms  used in  this  letter  agreement,  not
otherwise defined in this letter agreement,  shall have the meanings ascribed to
them in the Merger  Agreement.  The  provisions of this letter  agreement  shall
survive consummation of the transactions under the Merger Agreement.

    (1) Directors of Bank.  The directors of the Bank  immediately  prior to the
Effective  Time  together  with two members of Mahaska's  then current  board of
directors,  who shall be selected  by the  Directors  of  Mahaska,  shall be the
directors of the Bank at and after the Effective Time. Each such director of the
Bank will be  eligible  during his or her term of  service as a director  of the
Bank  to  participate  in  all  director   compensation  plans,   including  any
non-qualified stock option awards, on the same basis as nonemployee directors of
Mahaska or a Mahaska  Subsidiary  generally.  Mahaska  further  agrees that such
directors  shall be given full  credit for their past  service  with the Bank in
determining  participation in, eligibility for and vesting in benefits under the
director  compensation  plans.  Mahaska shall use its best efforts to cause each
such  director of the Bank (other than a current  member of the Mahaska Board of
Directors) to be re-elected for successive terms so that each such director will
serve for a minimum of three years after the Effective Time.

    (2)  Compensation  and Benefits for Current Company CEO and CFO. To maximize
the value to be  received  by  Mahaska in the  Merger,  Mahaska  believes  it is
essential  to  retain  the  services  of the  current  Company  CEO and CFO on a
long-term basis in order to integrate  operations,  to assure customer retention
and customer development, facilitate long-term strategic planning in Burlington,
Iowa  and  surrounding  market  area,  and to  otherwise  enhance  the  acquired
franchise.  Accordingly,  Mahaska  and each of the  current  Company CEO and CFO
shall on the date hereof enter into employment agreements in the form of Exhibit
D-1 (for the CEO) and  Exhibit  D-2 (for the CFO) to the Merger  Agreement  (the
"New  Employment  Agreements").  The  New  Employment  Agreements  shall  become
effective  at the  Effective  Time.  The Bank  shall pay to each of the  current
Company CEO and CFO a lump sum cash payment  immediately  prior to the Effective
Time in the amount of $120,000 and $90,000,  respectively,  in exchange for such
executives entering into the New Employment Agreements and thereby relinquishing
their economic  rights and benefits under their existing  employment  agreements
with the Bank.

    (3)  Salary  Continuation  Plans.  At the  Effective  Time,  or as  soon  as
thereafter as practicable, Mahaska agrees to establish Salary Continuation Plans
for the current  Company  CEO and CFO.  Such plans will be  consistent  with and
substantially  similar to those currently  provided or to be provided to certain
of Mahaska's senior  officers.  Such plans will provide for full credit for past
service  with  the  Company  and  the  Bank  for   purposes  of   participation,
eligibility,  vesting and accrual of benefits under the plans, including but not
limited to upon death of the executive the benefits payable shall be paid to the
executive's  designated  beneficiary.  In  no  event  will  the  annual  benefit
commencing  at age 55 be no less than  $20,000 or at age 65 no less than $50,000
for a period of 10 years for the current CEO, and the annual benefit  commencing
at age 65 be no less than $40,000 for a period of 10 years for the current CFO.

    (4) Group Health Plan. At or after the Effective Time, the Company Employees
shall be integrated  into the group health plans and  cafeteria  plan of Mahaska
and the Mahaska  Subsidiaries  in a manner whereby no Company  Employee shall be
subject to any gap in coverage or a pre-existing  condition  exclusion for which
coverage is  available  to him or her under the group health plan of the Company
or the  Bank  immediately  prior to the  Effective  Time.  Consistent  herewith,
Mahaska  shall  continue  the group health plan of the Company or the Bank after
the Effective  Time for those Company  Employees who would be subject to any gap
in coverage or  pre-existing  condition  exclusion as described above until such
time as they are not subject to such  conditions  under the group health plan to
be provided to them by Mahaska or a Mahaska Subsidiary.







    (5) Qualified  Plans. (a) Company ESOP. The Company ESOP will be merged into
the Mahaska ESOP at or as soon as practicable after the Effective Time.  Pending
the merger of such plans,  the Company  ESOP shall be  maintained,  operated and
administered for the exclusive benefit of those participants in the Company ESOP
as of the Effective Time and those former  participants  or their  beneficiaries
who have undistributed  account balances in the Company ESOP as of the Effective
Time, in all cases in compliance with ERISA,  the Code and all other  applicable
laws and  regulations.  No  amendment  or change  will be made by Mahaska to the
Company  ESOP which would  adversely  affect the rights of  participants  and/or
their  beneficiaries  and after the  merger  of the plans the  vesting  schedule
currently  contained in the Company ESOP shall continue to apply to the unvested
account balances of each participant as of the Effective Time.

    (b) Bank Defined  Benefit  Pension Plan.  This plan shall at the election of
the Company  either be (a) frozen as to  participation  as of the Effective Time
and  terminated at or as soon as  practicable  after the Effective  Time; or (b)
continued  for a  period  consisting  of the tax  year in which  the  Merger  is
consummated  and one tax year  thereafter  for the exclusive  benefit of Company
Employees  and persons  having  rights under the plan  immediately  prior to the
Effective  Time, in which case the plan shall be frozen as to  participation  at
the  expiration of the second tax period  stated  herein and  terminated on such
date or as soon  thereafter as is  practicable.  The Company shall  exercise its
election by written notice to Mahaska prior to the Effective Time.  Prior to any
termination  of the plan,  either the Bank or Mahaska,  whichever is applicable,
shall  cause  the  plan  to be  amended  to  allocate  excess  assets  on a plan
termination  basis to those  participants  in the plan on the date it is frozen;
and in the case where the plan is frozen after the Effective Time, excess assets
shall also be  allocated  to those  persons  who were  participants  in the plan
immediately  prior to the Effective Time who are no longer  participants  in the
plan as of its freeze date, to the extent  permitted by the plan and  applicable
laws and regulations,  including but not limited to, ERISA and the Code. As soon
as practicable after the receipt of a determination  letter for termination from
the Internal Revenue Service  relating to the termination of the plan,  benefits
will be distributed in accordance with the plan and, to the extent  permitted by
law,  participants or beneficiaries will be offered the right to roll over their
benefits  to another  qualified  plan of Mahaska  or to an  eligible  individual
retirement account.

    (6) Other Benefit Plans.  Ninety days after the Effective  Time, all Company
Employees  will  become  participants  in  Mahaska's  short-term  and  long-term
disability  plan,  group term life insurance  plan, and 401(k) plan on a uniform
and  nondiscriminatory  basis.  Company  Employees will be given full credit for
prior  years of  service  with  the  Company  and the  Company  Subsidiaries  in
determining  participation in,  eligibility for and vesting in benefits,  to the
extent applicable, in such Mahaska plans.

    Please  indicate  your  agreement  with the foregoing by signing one copy of
this letter in the space set forth below.

                                   MAHASKA INVESTMENT COMPANY

                                   By /s/ Charles S. Howard
                                      -----------------------------------------
                                      Its President and Chief Executive Officer

           Acknowledged and agreed to this 2nd day of February, 1999.

                                   MIDWEST BANCSHARES, INC.
            
                                   By /s/ William D. Hassel
                                      -----------------------------------------
                                      Its President and CEO



                                       -2-






    The  undersigned  have  executed  this Letter  Agreement  for the purpose of
agreeing in their individual capacities to provisions of items 2 and 3 above.

    William D. Hassel, individually

    /s/ William D. Hassel
    ---------------------                

Dated: February 2, 1999

    Robert D. Maschmann, individually

    /s/ Robert D. Maschmann
    -----------------------     

Dated: February 2, 1999



                                       -3-