Adults are mothlike, holding their wings rooflike over their backs. The forewings are hairy (instead of scaly like a moth’s). Colors are usually dark and drab, although the hindwings, usually hidden beneath the forewings, are often clear. The antennae are threadlike, many-segmented and long, usually as long as the rest of the body.
Larvae are aquatic, slender, with a segmented abdomen that is usually hidden within a portable protective case. The head has chewing mouthparts, and there are 3 pairs of legs at the front of the body. The case varies with species but is most typically created from tiny pieces of plants, sand grains or other detritus adhered or spun together into a tube or cone. Some cases are spiral like a snail shell. Some species don’t make cases at all.