Cal. Gov. Code § 10502

The committee shall consist of seven Members of the Senate and seven Members of the Assembly who shall be selected in the manner provided for in the Joint Rules of the Senate and Assembly. The committee shall elect its own chairman. Vacancies occurring in the membership of the committee between general sessions of the Legislature shall be filled in the manner provided for in the Joint Rules of the Senate and Assembly. A vacancy shall be deemed to exist as to any member of the committee whose term is expiring whenever such member is not reelected at the general election.