Rule XI, clause 5, Rules of the House of Representatives, provides that: “Witnesses appearing before the House or any of its committees shall be paid the same per diem rate as established, authorized, and regulated by the Committee on House Administration for Members, Delegates, the Resident Commissioner, and employees of the House, plus actual expenses of travel to or from the place of examination. Such per diem may not be paid when a witness has been summoned at the place of examination.”