supernumeraries

Webster's Dictionary (GCIDE)

1.A person or thing beyond the number stated. [1913 Webster]

2.A person or thing beyond what is necessary or usual; especially, a person employed not for regular service, but only to fill the place of another in case of need; specifically, in theaters, a person who is not a regular actor, but is employed to appear in a stage spectacle. [1913 Webster]