The resulting structure

Clarence John Hylander, Insects on parade, New York , MacMillan, 1957, p. 160.

Caddisfly larvae are unusual usual in being builders of portable homes. Sands, bits of gravel, twigs, parts of leaves are collected and cemented together by a silk produced in special gland opening into the mouth.
The resulting structure is an elongated case which serves as a portable home in which the larva spends most of its life ; with head projecting from the case , it lies alert for bits of food which drift by. Caddis-flies and their peculiar cases can be found on the underside of stones in streams. Some species go a step further in their engineering and construct cup-shaped nets to collect food, with the open portion facing upstream. The caddisfly makes daily trips from its nearby case to these buit feeding grounds. Dragonflies and Damselflies are…