(a) In the event of the death, resignation, disability, or absence from the state of the Speaker, the majority floor leader, as acting Speaker, shall exercise all the powers and duties of the Speaker when the General Assembly is not in session, but the exercise of such powers and duties by the acting Speaker shall continue only until the General Assembly shall meet or until the disability or absence from the state of the Speaker is removed, whichever shall first occur. In the event of the death, resignation, disability, or absence from the state of such majority floor leader, then the following persons shall succeed to the office of acting Speaker: The chairman of each of the committees of reference of the House in the order listed in Rule 25 (a) of these rules.