Continuance of proceedings requires successor-in-interest to apply within the prescribed period; tribunal may extend for sufficient cause. Proceedings abate on the death, adjudication as insolvent, or winding up of a party unless the successor-in-interest, executor, receiver, liquidator or other legal representative applies for continuance; such application must be made within sixty days of the event, though the Appellate Tribunal may allow a later application if prevented by sufficient cause.