Fred Eastman, The Open Book of wild life: an introduction to nature study, Londres, A. & C. Black, 1941, pp. 58-60.

These aquatic caterpillars, as we may call them, are often known as caddis «  worms », and it is they that are the insects tailors to which we have just referred. They seem instinctively to know that their tender little bodies are highly attractive dainties to the preying inhabitants of the water, and very early in life they begin to clothe themselves in suits of their own making. As a general rule, the larva of each species of caddis fly keeps to its own particular kind of suit ; and with a  little careful searching, you can find an extraordinary interesting variety of these –tailor-made garments in suitable ponds and streams almost everywhere. With the aid of silk which is made from their own saliva, the caddis tailors bind together such things as pieces of leaves or stems, tiny bits of thin twigs or straws, grains of sand, little fragments of stone or shells, or even the whole shells of very small water snails, often with the snails themselves still living inside them. Caddis cases are left open at both ends, and from the larger end the little caterpillar can poke its head and its six legs, and so pull itself aling. In course of time each larva, in its own particulary way, closes both ends of its tubular case and  changes to a pupa inside.