William Bingley, Animal biography or, Popular Zoology, vol. IV, Londres, 1829, p. 125

The larvae, when hatched, form for themselves tubes of silk, the interior of which is smooth and polished, and to the exterior of which they attach fragments of different substances, thus constituting a strong defence against the attempts of their enemies. Some of the species employ for this purpose, bits of leaves, straw, grass or rushes ; others adopt the shells of small aquatic snails ; others, grains of sand ; and others, employ several different kinds mixed together. They contrive to make their habitations nearly in equilibrium with the water, by adding a bit of wood when too heavy, and some heavier substance when too light.