Anonyme, Wildlife Handbook, North Pacific Region, 1944, p. 45. http://babel.hathitrust.org

The tiny larva build itself a portable case of sand grains or bits of debris or spins itself a net or silken tube in which it lives under water. Shelters are enlarged as the animal grows. Each species builds its own type of cases and the different kinds of caddisflies may be recognized by the architecture of their larva cases.