Chironomidae (informally known as chironomids or non-biting midges) are a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many species superficially resemble mosquitoes but they lack the wing scales and elongate mouthparts of the Culicidae. This is a large group of insects with over 5000 described species and 700 species in North America alone. Males are easily recognized by their plumose antennae. Adults are sometimes known as "lake flies" in parts of Canada, as "sand flies", "muckleheads, or "muffleheads in various regions of the USA Great Lakes area, and as "blind mosquitoes" in Florida, USA.
Larvae can be found in almost any aquatic or semiaquatic habitat, including treeholes, bromeliads, rotting vegetation, soil, and in sewage and artificial containers. Larvae of some species are bright red in color due to hemoglobin; these are often known as "bloodworms".
The larvae (bloodworm) are an important food item for fish such as trout, as are also the pupae moments before emergence. The Flying midges themselves are also eaten by fish, and insectivorous birds such as swallows and martins. They are importnt to fly anglers, who tie imitators to catch the trout.