cribellum
From ZooTerms (Dictionary of Invertebrate Zoology)
cribellum (noun; Latin cribrum, sieve): 1. (Arthropoda: Chelicerata) In spiders, a sieve-like, transverse plate, usually divided by a delicate keel into two equal parts, located in front of the spinnerets; the modified anterior median spinnerets.
2. (Arthropoda: Insecta) A sieve-like chitinous plate near the upper surface of the mandibles.
