Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 175, § 180I

If a liquidation proceeding is commenced in a reciprocal state against an insurer of which such state is the domiciliary state, claimants against such insurer who reside within this commonwealth may file claims either with the ancillary receiver, if any, appointed in this commonwealth or with the domiciliary receiver; provided, that all such claims shall be filed on or before the last date fixed by the court for the filing of claims in the domiciliary proceeding.

In any such proceeding, contested claims belonging to claimants residing in this commonwealth may be proved (a) in the domiciliary state as provided by the law of such state, or (b), if ancillary proceedings have been commenced in this commonwealth, in such ancillary proceedings. In the event that any such claimant elects to prove his claim in this commonwealth, he shall file his claim with the ancillary receiver in the manner provided by decree or rule of the court in which the proceeding is pending and he shall give, or cause to be given, notice in writing to the receiver in the domiciliary state, either by registered mail or by personal service. Such notice shall be given at least forty days prior to the date set for hearing, and shall contain a concise statement of the amount of the claim, the facts on which the claim is based, and the priorities asserted, if any. If the domiciliary receiver, within thirty days after the giving of such notice, shall give notice in writing to the ancillary receiver and to the claimant, either by registered mail or by personal service, of his intention to contest such claim, the domiciliary receiver shall be entitled to appear in any proceeding in the commonwealth involving the adjudication of the claim. The final allowance of a claim by a court of the commonwealth shall be accepted as conclusive as to its amount and priority, if any, against special deposits or other security located within the commonwealth.