Paul H. Bratton, « Of Caddis Flies Kingfishers and Trout », Richmond (VA), Virginia Wildlife, vol. XXXVII, n°3, septembre 1976, p. 26
First we headed for a small feeder streams to search for the three-inch conglomerations of twigs and leaves that form the case of the caddis fly’ larva.
The caddis larva spends most of its life in a home constructed from material found in the stream bed. Those larva living in swifter water often use pebbles and sand for ballast, while those in gentler currents might use twigs and leaves. The caddis glues these materials into the form of a slightly tapered funnel with its head at the larger end and its body entirely enclosed in the case. The case are numerous in most trout streams and the trout often swallow the entire caddis case, leaving the job of separating the larva from the debris to it digestive tract.