; order Diptera, suborder Nematocera)
Family of delicate, gnat-like flies, in which the males have conspicuous, plumose antennae, and those of females are pilose. The head is usually overhung, and often concealed, by the thorax. Mouth-parts are poorly developed. Anterior wing veins are more prominent than posterior ones. Adults bear some resemblance to Culicidae, but can be distinguished by their unscaled wings. Adults fly in large numbers at sunset near standing bodies of water. The swarms comprise mainly males, and mating occurs when a female flies into a swarm. Eggs are laid in a mass, or ribbon of clear, mucus-like jelly. Larvae are almost all aquatic, or mud-dwellers that live in tubes. Some species have larvae containing haemoglobin as an adaptation to life in anoxic substrates. Some species can reproduce parthenogenetically, and paedogenesis has been recorded in others. There are some 2000 described species.
Subjects: Zoology and Animal Sciences.