40 ILCS 5/9-216
The county treasurer shall be ex-officio the treasurer and custodian of the fund and shall furnish to the board a bond of such amount as the board designates, which shall indemnify the board against any loss which may result from any action or failure to act by him or any of his agents. Fees and charges incidental to the procuring of such bond shall be paid by the board. In addition to tax and employee contributions constituting the fund, the treasurer is authorized to receive and deposit in the fund warrants issued by this State representing deductions from the salary of the employees designated in paragraph (e) of Section 9-108, but only for such period as they remain members of the fund, and such other contributions of State funds as may be authorized by law.
40 ILCS 5/9-216