The Chironomidae is a large and diverse family of flies. They are commonly known as "non-biting midges." There are over 20,000 species known world-wide, including 2,000 in the Nearctic. Adult midges are relatively small (1-20 mm long), with narrow bodies and long legs. They are often confused with mosquitos, but no members of this family are blood-feeders (hence the "non-biting" part of the common name). Adults, if they feed at all, feed on nectar or similar substances. Midge larvae are nearly all aquatic or sub-aquatic, and are a very important part of many freshwater ecosystems. Both in numbers and in diversity, they are often the largest group of primary consumers in these systems. Species of Chironomidae can be found in an enormous variety of aquatic habitats, from brackish estuaries to pools in tree-holes, and from low-oxygen lake sediments to fast-flowing mountain streams. (Coffman and Ferrington Jr., 1996; Foote, 1987; McCafferty, 1983)