The Nematocera (the name meaning "thread-horns") are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies except for species from suborder Brachycera (the name meaning "short-horns"), which includes more commonly known species such as the housefly or the common fruit fly. The equivalent clade to Nematocera is the whole Diptera, with Brachycera as a subclade. Families in Nematocera include mosquitoes, crane flies, gnats, black flies, and multiple families commonly known as midges. The Nematocera typically have fairly long, fine, finely-jointed antennae. In many species, such as most mosquitoes, the female antennae are more or less threadlike, but the males have spectacularly plumose antennae.

The larvae of most families of Nematocera are aquatic, either free-swimming, rock-dwelling, plant-dwelling, or luticolous. Some families however, are not aquatic; for instance the Tipulidae tend to be soil-dwelling and the Mycetophilidae feed on fungi such as mushrooms. Unlike most of the Brachycera, the larvae of Nematocera have distinct heads with mouthparts that may be modified for filter feeding or chewing, depending on their lifestyles.

The pupae are orthorrhaphous which means that adults emerge from the pupa through a straight, longitudinal seam in the dorsal surface of the pupal cuticle.

The bodies and legs of most adult Nematocera are elongated, and many species have relatively long abdomens.

Males of many species form mating swarms like faint pillars of smoke, competing for females that visit the cloud of males to find a mate.

...