Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 176P, § 21

Death or annuity benefits shall be payable to any beneficiary designated by the member, but the society may by its by-laws make restrictions as to whom may be beneficiaries. Each member shall have the right to change his beneficiary from time to time in accordance with the by-laws of the society. No beneficiary shall have or obtain any vested interest in such benefits until the same have become due and payable upon the death of the member. No contract under this chapter, except where an incorporated charitable institution or home is made a beneficiary in accordance with the by-laws of the society, shall be valid that is conditioned upon an agreement or understanding that the person to whom the death or annuity benefit is made payable shall pay the periodic or other contributions of the member.