Cribellum

·noun A peculiar perforated organ of certain spiders (Ciniflonidae), used for spinning a special kind of silk.

cribellum
crībellum, i, n. dim. [cribrum], a small sieve (late Lat.), Pall. Febr. 24; id. Jun. 11. ...

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.