David Cabot, Irish Pond Life, Ill. Michael McNamee, n°35 of the Irish Environmental Library Series, Folens, circa 1975, p. 139.
The caddis-fly larva, superficialy resembling a caterpillar, is called a caddis-worm or stick-worm is an extraordinay looking creature. The soft-bodied larva builds a special protective case around its lower body using small stones, twigs, leaf fragments, shells, sand or whatever material is available. The cases are usually small, rarely more than 2 cm long. Some caddis-fly larvae build their case with one kind of material while others use a mixture of materials. There are a few special caddis-fly larvae which never build a protective case and live quite freely. The particles are stuck to a silk envelope which the larva spins around itself before building its portable home.