Flies are insects of the order Diptera, the name being derived from the Greek δι- di- "two", and πτερόν pteron "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced mechanosensory organs known as halteres, which act as high-speed sensors of rotational movement and allow dipterans to perform advanced aerobatics. Diptera is a large order containing an estimated 1,000,000 species including horse-flies, crane flies, hoverflies and others, although only about 125,000 species have been described.
A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found on practically every land area outside permanently arid deserts and the frigid zones. Some midges, such as many Phlebotominae and Simuliidae, are vectors of various diseases. Many others play useful roles as prey for insectivores, such as various frogs and swallows. Others are important as detritivores, and form part of various nutrient cycles. The habits of midges vary greatly from species to species, though within any particular family, midges commonly have similar ecological roles.
The Nematocera are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. Major families in the suborder include the mosquitoes, crane flies, gnats, black flies, and a group of families described as midges.
Cecidomyiidae is a family of flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small insects usually only 2–3 mm (0.079–0.118 in) in length; many are less than 1 mm (0.039 in) long. They are characterised by hairy wings, unusual in the order Diptera, and have long antennae. Some Cecidomyiids are also known for the strange phenomenon of paedogenesis in which the larval stage reproduces without maturing first. In some species, the daughter larvae consume the mother, while in others, reproduction occurs later on in the egg or pupa.
Sphaeroceridae are a family of true flies in the order Diptera, often called small dung flies, lesser dung flies or lesser corpse flies due to their saprophagous habits. They belong to the typical fly suborder Brachycera as can be seen by their short antennae, and more precisely they are members of the section Schizophora. There are over 1,300 species and about 125 genera accepted as valid today, but new taxa are still being described.
The Nymphomyiidae are a family of tiny (2 mm) slender, delicate flies (Diptera). Larvae are found among aquatic mosses in small, rapid streams in northern regions of the world, including northeastern North America, Japan, the Himalayas, and eastern Russia. Around a dozen extant species are known, with two fossil species found in amber, extending back to the Mid Cretaceous. Under an alternative classification, they are considered the only living representatives of a separate, suborder called Archidiptera which includes several Triassic fossil members. The family has characteristics associated with the Nematocera as well as the Brachycera. The antennae are shortened as in the Brachycera and these flies are long, having a snout with vestigeal mouthparts, non-differentiated abdominal segments with large cerci. The wings are narrow and hair-fringed and have very weak venation. They are known to form cloud-like swarms in summer and the short-lived non-feeding adults have wings that fracture at the base shortly after mating.
Braulidae, or bee lice, is a family of true flies (Diptera) with seven species in two genera, Braula and Megabraula. They are found in honey bee colonies due to their phoretic, inquiline, and kleptoparasitic relationships with the bees. Similar in appearance but not closely related to keds, these flies are also small, wingless, and occasionally mistaken for mites or lice, hence their common name.
The Micropezidae are a moderate-sized family of acalyptrate muscoid flies in the insect order Diptera, comprising about 500 species in about 50 genera and five subfamilies worldwide,. They are most diverse in tropical and subtropical habitats, especially in the Neotropical Region.
The Limoniinae are a paraphyletic assemblage of genera within the crane flies, Tipulidae, although they can usually be distinguished by the way the wings are held at rest. Limoniines usually hold/fold the wings along the back of the body, whereas other tipulids usually hold them out at right angles. Snow flies such as Chionea scita have no wings at all. Limoniines are also usually smaller than other tipulids, with some exceptions.
The Anisopodidae are a small cosmopolitan family of gnat-like flies known as wood gnats or window-gnats, with 154 described extant species in 15 genera, and several described fossil taxa. Some species are saprophagous or fungivorous. They are mostly small to medium-sized flies, except the genera Olbiogaster and Lobogaster, which are large with bizarrely spatulated abdomens. Their phylogenetic placement is controversial. They have been proposed to be the sister group to the higher flies, the Brachycera. Some authors consider this group to be four distinct families – Anisopodidae, Mycetobiidae, Olbiogastridae, and Valeseguyidae.
Clusiidae or "druid flies" is a family of small, thin, yellow to black acalyptrate flies with a characteristic antenna and with the wing usually partially infuscated. They have a cylindrical body. The head is round, the vertical plate reaches the anterior margin of the frons and the vibrissae on the head are large. The costa is interrupted near subcosta and the latter developed throughout length. Larvae are found in the bark of trees, the flies on trunks. The larvae are notable for their ability to jump. Males of many species in the subfamily Clusiodinae have been observed while engaged in lekking behaviour. There are hundreds of species in 14 genera found in all the Ecoregions, although most species occur in tropical regions. The type genus is Clusia Haliday, 1838.
Bibionidae is a family of flies (Diptera) containing approximately 650–700 species worldwide. Adults are nectar feeders and emerge in numbers in spring. Because of the likelihood of adults flies being found in copula, they have earned colloquial names such as "love bugs" or "honeymoon flies".
The Celyphidae, commonly known as beetle flies or beetle-backed flies, are a family of flies. About 115 species in about 9 genera are known chiefly from the Oriental and Afrotropic biogeographic regions with one lineage in the New World.
The Neriidae are a family of true flies (Diptera) closely related to the Micropezidae. Some species are known as cactus flies, while others have been called banana stalk flies and the family was earlier treated as subfamily of the Micropezidae which are often called stilt-legged flies. Neriids differ from micropezids in having no significant reduction of the fore legs. Neriids breed in rotting vegetation, such as decaying tree bark or rotting fruit. About 100 species are placed in 19 genera. Neriidae are found mainly in tropical regions, but two North American genera occur, each with one species, and one species of Telostylinus occurs in temperate regions of eastern Australia.
Senostoma is a genus of parasitoid tachinid flies in the family Tachinidae. Endemic to Australasia, the flies are medium-sized, bristly, and long-legged.
The Cylindrotomidae or long-bodied craneflies are a family of crane flies. About 115 species in 9 genera occur worldwide.
Pelecorhynchidae is a small family of flies. All of the genera were originally placed in the family Rhagionidae, and their elevation to family rank has been controversial. Other phylogenetic analyses have supported Pelecorhynchidae as a distinct clade from Rhagionidae. The adults of Pelecorhynchus mostly feed on nectar of Leptospermum flowers. Larvae have been collected in the damp margins of swamp areas, where they feed on earthworms.
Pontomyia is a genus of flightless marine midges belonging to the subfamily Chironominae in the Chironomidae family. Insects in marine environments are extremely rare while flightlessness, extreme sexual dimorphism, and an extremely short adult life span contribute to making these midges unusual among insects. They are known from the shores of islands in the Indian, Atlantic and Pacific Oceans.
A gnat is any of many species of tiny flying insects in the dipterid suborder Nematocera, especially those in the families Mycetophilidae, Anisopodidae and Sciaridae. They can be both biting and non-biting. Most often they fly in large numbers, called clouds. "Gnat" is a loose descriptive category rather than a phylogenetic or other technical term, so there is no scientific consensus on what constitutes a gnat. Some entomologists consider only non-biting flies to be gnats. Certain universities and institutes also distinguish eye gnats: the Smithsonian Institution describes them as "non-biting flies, no bigger than a few grains of salt, ... attracted to fluids secreted by your eyes".
Scaptomyza flava is an herbivorous leaf mining fly species in the family Drosophilidae. In Latin, flava means golden or yellow. The fly is amber to dark brown in color and approximately 2.5 mm in length. In Europe and New Zealand the larvae are pests of plants in the order Brassicales, including arugula, brassicas, broccoli, Brussels sprouts, bok choy, cabbage, canola, cauliflower, horseradish, kale, kohlrabi, napa cabbage, nasturtium, radish, rapini, rutabaga, turnip, wasabi and watercress. In New Zealand, its range has expanded to include host species that are intercropped with salad brassicas, including gypsophila, otherwise known as baby's breath, which is in the pink family (Caryophyllaceae) and the pea in the Fabaceae. More typically, S. flava is oligophagous within the Brassicales. Scaptomyza are unusual within the Drospophilidae because the group includes species that are truly herbivorous. Other herbivorous drosophilids include D. suzukii, which attacks fruit very early during ripening and species within the genus Lordiphosa, from Africa and Asia, which also include leaf miners. Most drosophilids feed on microbes associated with decaying vegetation and sap fluxes.
