25 Pa. Stat. § 3164
The Secretary of the Commonwealth shall issue certificates of election to the persons elected members of the Senate and House of Representatives of the Commonwealth, and between the hours of twelve noon and one P.M. on the first Tuesday in January of each odd-numbered year, present before the Senate and the House of Representatives the several returns of the elections of members of the respective houses: Provided, however, That if the General Assembly shall be convened in extraordinary session during the month of December next following their election, the said returns shall be presented as aforesaid, on the first day of said extraordinary session. In case of a special election occurring during a session of the General Assembly, he shall present the returns thereof to the proper House as soon as received and tabulated by him.
25 P.S.§ 3164