There are about 1200 species of the small moth-like insects known as Caddis-flies. They live near streams, rivers and lakes with larvae that live in the water. Most larvae excrete silk used to build nests or cases that they then use as housing or to catch food. Caddis-flies stay in the pupa stage for months. Once they emerge as adults in late spring or early fall, they only live up to 2 months and their only purpose is to reproduce by laying their eggs in the water. Caddis-flies are not harmful to humans and can be an indication of how healthy a body of water is. Caddis-flies are an important food source for fish, birds, frogs and insects.