Mowbray Edward Tuttle, The Book of rural life knowledge and inspiration a guide to the best in Modern Living, Chicago, Bellows-Durham, 1925, p. 804.
Caddis , Kad’is,
Fly, an insect which looks somewhay like a small dark- colored moth. Its wings have a few scales similar to those on some moths, but it has no mouth parts after it becomes full-grown.
Caddis flies are sometimes drawn in large numbers to street lights, but even then then do not attract much attention, and are not conspicious insects at any time.
The larvae, or caddis worms, as they are called, are found usually in running streams and beneath rocks. Here they form tubelike cocoons, made of small bits of wood or of pebbles, grains of sand or even mud. These are lined with silk and enlarged as the insect grows. They are attached temporarily at first, to the rocks, and the insect projects the front end of the body to securefood or to move from place to place , dragging the cocoon by the rear of the body which remains within at all times. When the larva is full-grown the entrance is closed, and the worm transforms, within the cocoon, to the caddis fly. The caddis flies are widely distributed and may be observed in almost any creek. They are best studied in such natural places, since they do not thrive elsewhere.