Mississippi constitution
Article 4
Section 36

The Legislature shall meet at the seat of government in regular session on the Tuesday after the first Monday of January of the year A.D., 1970, and annually thereafter, unless sooner convened by the Governor; provided, however, that such sessions shall be limited to a period of one hundred twenty-five (125) calendar days for regular 1972 session and every fourth year thereafter, but ninety (90) calendar days for every other regular session thereafter. Provided further that the House of Representatives, by resolution with the Senate concurring therein, and by a two-thirds (2/3) vote of those present and voting in each house, may extend such limited session for a period of thirty (30) days with no limit on the number of extensions to each session.