The circuit solicitors of the various judicial circuits of this State shall each receive such annual salary, payable monthly, as may be provided by the General Assembly. Such salaries shall be in lieu of all charges against the State and the counties. All costs from defendants shall be paid over by each solicitor to the county treasurer for the use of the State.

It shall be the duty of the solicitors to perform the services required in §§ 1-7-340 and 1-7-350, and in no instance, civil or criminal, shall they receive for such services any additional compensation, except that they shall be entitled to expense allowance, as provided for State employees and officers, when performing such services outside of their respective circuits.