The components

Albro Tilton GaulThe Wonderful World of Insects, Londres, Victor Gollancz, Sidgwick & Jackson, 1953, p. 112.

With this silk, the larvae build little tubes of sand grains, pebbles, sticks, or leaves, depending upon the habitual preference of the species. These little tube assemblies are large enough to surround the larva, who lives within. The components of these tube-homes are assembled with great care. The cases made of sand are so neatly constructed that each sand grain exactly fits the grains adjacent. These caddis-cases, or tube-homes, are carried around by the larvae.