Section 90. Whoever employs a child under sixteen, or whoever procures, or, having under his control a child under sixteen, permits him to be employed in violation of section eighty-six, shall be punished by a fine of not less than ten nor more than fifty dollars or by imprisonment for not more than one month; and whoever continues to employ a child under sixteen in violation of said section, after being notified thereof by a supervisor of attendance or by an inspector, shall for every day thereafter while such employment continues be punished by a fine of not less than fifty nor more than two hundred dollars or by imprisonment for not more than two months; and whoever forges, or procures to be forged, or assists in forging a certificate of birth or other evidence of the age of such child, and whoever presents or assists in presenting a forged certificate or evidence of birth to the superintendent of schools or to a person authorized by law to issue permits, for the purpose of fraudulently obtaining the employment permit required by section eighty-six, shall be punished by a fine of not less than ten nor more than five hundred dollars or by imprisonment for not more than one year, or both. Whoever, being authorized to sign an employment permit, knowingly certifies to any materially false statement therein shall be punished by a fine of not less than ten nor more than two hundred dollars. Whoever, without authority, alters an employment permit after the same is issued shall be punished by a fine of ten dollars.