Most larvae feed on algae or small aquatic plants. Some have narrow spotted or clear wings. Larvae are tiny, whitish, elongate, or wormlike, and are found in sand, mud, decaying vegetation, and water in tree holes. Legs of all species break off easily so that perfect specimens are difficult to maintain in an insect collection. Many have patterned wings and resemble mosquitoes.
Maggots are legless, have poorly developed heads, and are about one inch long when mature.
They are usually associated with poorly-drained soils and sometimes occur in large, concentrated numbers. They are sometimes mistaken as cutworms. During peak emergence, extremely large populations of non-biting midges may create much annoyance simply by accumulating in freshly applied paints, hanging onto outdoor laundry, clustering on screens, etc. Summer resorts along lakes and other water frontage may have houses and buildings covered with these midges that enter around vent openings, air conditioning units, windows, doors, etc. The following day, these midges are found dead on window sills throughout the building.