When a salaried official stenographer renders service in a county other than the one for which he is appointed, the justice shall allow him his reasonable and actual expenses for transportation, food and lodging, to be paid by the commonwealth. At the conclusion of his assignment he shall send a statement of the dates when he rendered service in such county, attested by the clerk of the court, to the state treasurer.
Mass. Gen. Laws ch. 221, § 90A