Missouri Constitution Article III Sec. 16 – Compensation, mileage allowance and expenses of general assembly members
Senators and representatives shall receive from the state treasury as salary such sums as are provided by law. No law fixing the compensation of members of the general assembly shall become effective until the first day of the regular session of the general assembly next following the session at which the law was enacted. Upon certification by the president and secretary of the senate and by the speaker and chief clerk of the house of representatives as to the respective members thereof, the state comptroller shall audit and the state treasurer shall pay such compensation without legislative enactment. Until otherwise provided by law senators and representatives shall receive one dollar for every ten miles traveled in going to and returning from their place of meeting while the legislature is in session, on the most usual route.
Until otherwise provided by law, each senator or representative shall be reimbursed from the state treasury for the actual and necessary expenses incurred by him in attending sessions of the general assembly in the sum of ten dollars ($10.00) per day for each day on which the journal of the senate or house respectively shows the presence of such senator or representative. Upon certification by the president and secretary of the senate and by the speaker and chief clerk of the house of representatives as to the respective members thereof, the state comptroller shall approve and the state treasurer shall pay monthly such expense allowance without legislative enactment.