Otto Eggeling & Frederik Ehrenberg, The Freshwater aquarium and Its Inhabitants, A Guide for the Amateur Aquarist, New York, Henry Holt & Co., pp. 298-299, 1912.

It is know as the caddis, or case worm, a soft-bodies, six-legged being which, to protect itself against its countless ennemies, constructs a tube or bag like case, smooth on the inside, but covered on the outside with small stones, little shells and parts of aquatic plants. These the larva joins in such a manner that the result of its labor resembles very closely the bottom  of the pond or stream in which it lives. As soon the larva leaves the egg it will surround itself with some small bits of the material closes at hand, later extending the covering in proportion to its own growth.