Section 91. The employer of any minor between fourteen and sixteen who is required by section twenty-two of chapter seventy-one to attend a continuation school or course of instruction shall cease forthwith to employ such minor when notified in writing by the superintendent of schools, or by his representative duly authorized in writing, having jurisdiction over such minor’s attendance, of his non-attendance in accordance with said section. An employer failing to comply with this section shall be punished by a fine of not less than ten nor more than one hundred dollars.