2 U.S.C. § 389: Officer and witness fees

(a) Each judge, clerk of court, or other officer who issues any subpena or takes a deposition and each person who serves any subpena or other paper herein authorized shall be entitled to receive from the party at whose instance the service shall have been performed such fees as are allowed for similar services in the district courts of the United States. (b) Witnesses whose depositions are taken shall be entitled to receive from the party at whose instance the witness appeared the same fees and travel allowance paid to witnesses subpenaed to appear before the House of Representatives or its committees.