Section 81. Any parent, guardian or custodian having a minor under his control who compels or permits such minor to work in violation of any provision of sections sixty to seventy-four, inclusive, or knowingly certifies to any materially false statement for the purpose of obtaining the illegal employment of such minor, shall for a first offence be punished by a fine of not less than two nor more than ten dollars or by imprisonment for not more than five days, or both; and for a subsequent offence by a fine of not less than five nor more than twenty-five dollars or by imprisonment for not more than ten days, or both.