With the aid of silk

Richard Morse, The Open Book of Wild Life, Londres, 1941, p. 58.

These aquatic caterpilars, as we many call them, are often known as caddis « worms », and it is they that are the insect tailors to which we have just referred. They seem instinctively to know thaty 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 keps to its own particular kind of suit; and with a little careful searching, you can find an extraordinarily interesting variety of these tailor-made garments in suitable ponds ans 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 shell, or even the whole shells of very small water snails, often with the snails themselves still living inside them.