Pa. Const. art. II, § 9

Election of officers; judge of election and qualifications of members. The Senate shall, at the beginning and close of each regular session and at such other times as may be necessary, elect one of its members President pro tempore, who shall perform the duties of the Lieutenant Governor, in any case of absence or disability of that officer, and whenever the said office of Lieutenant Governor shall be vacant. The House of Representatives shall elect one of its members as Speaker. Each House shall choose its other officers, and shall judge of the election and qualifications of its members.