Combination

Dave WhitlockL.L. Bean Fly Fishing Handbook, Lyons Press, 1984, p. 71-72.

Many species of caddisfly larva construct a case which they live. These cases are made uniquely according to species from glue and a silklike filament in combination with aquatic plant pieces, sand grains, or terrestrial plant part. The cases are for protection and camouflage. Along the bottom, they look like short sticklike structures.

whitlock-1984