What does "caddis" mean?

Caddis: The larva of a caddice fly. These larvæ generally live in cylindrical cases, open at each end, and covered externally with pieces of broken shells, gravel, bits of wood, etc. They are a favorite bait with anglers. Called also caddice worm, or caddis worm. Caddice fly (Zoöl.), a species of trichopterous insect, whose larva is the caddice.