Caddisflies look very much like small moths. Depending on the species, they range from 4 mm to 4 cm in length. They have long slender antennae and vestigial mouthparts that enable them to ingest liquid food only.
Two pairs of dark membranous wings, which are folded roof-like over the abdomen when at rest, are located on the thorax. The wings are covered with tiny hairs that give them a downy look.
The cylindrical abdomen usually tapers off to a pair of appendages in females and to at least two pairs in males.