Pennsylvania constitution
Article II: the legislature
Section 6

No Senator or Representative shall, during the time for which he was elected, be appointed to any civil office under this Commonwealth to which a salary, fee of perquisite is attached. No member of Congress or other person holding any office (except of attorney-at law or in the national guard or in a reserve component of the armed forces of the United States) under the United States of this Commonwealth to which a salary, fee or perquisite is attached shall be a member of either House during his continuance in office.