Section 25. The compensation of traverse jurors impanelled to try cases of murder in the first degree shall be sixteen dollars, and that of all other traverse jurors and of grand jurors fourteen dollars, for each day's service; provided, however, that jurors held under restraint by order of the court shall, in cases of murder in the first degree, receive twenty-two dollars and, in all other cases, twenty dollars for each day's service while under restraint. All jurors shall receive for each day of actual attendance eight cents a mile for travel out and home, but not for such time as the jury is held under restraint, by order of the court, at the expense of the commonwealth. If the expense of a juror who attends court, necessarily and actually incurred for transportation out and home once in each day, exceeds the amount of the said allowance for travel, he shall be allowed the amount of such expense in lieu of the said travel allowance. If a grand or traverse juror is required to be in attendance for five or more consecutive days he shall receive his fees not later than the end of every fifth day of such attendance.