Mass. Gen. Laws ch. 118C, § 3
(a) The state agency, with the approval of the governor, is hereby authorized to enter on behalf of the commonwealth into an agreement with the Federal Security Administrator, consistent with the terms and provisions of this chapter, for the purpose of extending the benefits of the federal old age and survivors insurance system to employees of instrumentalities, with respect to services specified in such agreement which constitute ''employment'' as defined in section two. Such agreement may contain such provisions relating to coverage, benefits, contributions, effective date, modification and termination of the agreement, administration and other appropriate provisions as the state agency and the Federal Security Administrator shall agree upon, but, except as may be otherwise required by or under the Social Security Act as to the services to be covered, such agreement shall provide in effect that—