Missouri constitution
Article III: legislative department
Section 16

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.