John William Douglas, The World of Insects : A guide to its Wonders, Londres, John Van Voorst, 1856.

The well-know caddis-worms, which live in water, in portable cases composed of bits of vegetable matter and shells of aquatic Mollusca spun together, are the larvae of the Phryganae, or caddis-flies of anglers. Some of the cases are very much like those of some of the Psychidae on land, and the inhabitant projects its thoracic segments in a similar manner to those larvae when it moves about.