Rule 2.6.  Acting Speaker

The Speaker or Speaker Pro Tempore may call upon a member to assume the duties of the presiding officer for a limited period, but in no case shall the period extend beyond adjournment each day.  The member so appointed to preside shall be designated Acting Speaker.  In the absence of the Speaker and the Speaker Pro Tempore, the Clerk, or, in the Clerk's absence, the employee performing the duties of Clerk shall call a member to serve as Acting Speaker.

Mason's Manual: Sec. 579(4)

HR 3, 1973; HR 4, 1978.