In travelling

Leon A. HausmanFresh-Water Life, New York, G.P. Putnam’s Sons, 1950, p. 69.

Caddis worm live in little portable cases and tubes on the bottoms of ponds and streams, which they construct of a variety of materials such as bits of wood, leaves, sand grains. The head and legs of the worm are projected from the front of the case in travelling.