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.
Crane fly is a common name referring to any member of the insect family Tipulidae. Cylindrotominae, Limoniinae, and Pediciinae have been ranked as subfamilies of Tipulidae by most authors, though occasionally elevated to family rank. In the most recent classifications, only Pediciidae is now ranked as a separate family, due to considerations of paraphyly. In colloquial speech, crane flies are sometimes known as "mosquito hawks", "skeeter-eater", or "daddy longlegs",. The larvae of crane flies are known commonly as leatherjackets.
Mayflies are aquatic insects belonging to the order Ephemeroptera. This order is part of an ancient group of insects termed the Palaeoptera, which also contains dragonflies and damselflies. Over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families.
The Asiloidea comprise a very large superfamily insects in the order Diptera, the true flies. It has a cosmopolitan distribution, occurring worldwide. It includes the family Bombyliidae, the bee flies, which are parasitoids, and the Asilidae, the robber flies, which are predators of other insects.
The Phoridae are a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their escape habit of running rapidly across a surface rather than taking to the wing. This behaviour is a source of one of their alternate names, scuttle fly. Another vernacular name, coffin fly, refers to Conicera tibialis. About 4,000 species are known in 230 genera. The most well-known species is cosmopolitan Megaselia scalaris. At 0.4 mm in length, the world's smallest fly is the phorid Euryplatea nanaknihali.
Snakeflies are a group of predatory insects comprising the order Raphidioptera with two extant families: Raphidiidae and Inocelliidae, consisting of roughly 260 species. In the past, the group had a much wider distribution than it does now; snakeflies are found in temperate regions worldwide but are absent from the tropics and the Southern Hemisphere. Recognisable representatives of the group first appeared during the Early Jurassic. They are a relict group, having reached their apex of diversity during the Cretaceous before undergoing substantial decline.
The Asilidae are the robber fly family, also called assassin flies. They are powerfully built, bristly flies with a short, stout proboscis enclosing the sharp, sucking hypopharynx. The name "robber flies" reflects their expert predatory habits; they feed mainly or exclusively on other insects and, as a rule, they wait in ambush and catch their prey in flight.
The Tephritoidea are a superfamily of flies. It has over 7,800 species, the majority of them in family Tephritidae.
Nerioidea is a superfamily of Acalyptratae flies.
The Brachyceran infraorder Muscomorpha is a large and diverse group of flies, containing the bulk of the Brachycera, and, most of the known flies. It includes a number of the most familiar flies, such as the housefly, the fruit fly, and the blow fly. The antennae are short, usually three-segmented, with a dorsal arista. Their bodies are often highly setose, and the pattern of setae is often taxonomically important.
The Agromyzidae are a family commonly referred to as the leaf-miner flies, for the feeding habits of their larvae, most of which are leaf miners on various plants.
Dolichopodidae, the long-legged flies, are a large, cosmopolitan family of true flies with more than 7,000 described species in about 230 genera. The genus Dolichopus is the most speciose, with some 600 species.
Empididae is a family of flies with over 3,000 described species occurring worldwide in all the biogeographic realms but the majority are found in the Holarctic. They are mainly predatory flies like most of their relatives in the Empidoidea, and exhibit a wide range of forms but are generally small to medium-sized, non-metallic and rather bristly.
The Lauxaniidae are a family of acalyptrate flies. They generally are small flies with large compound eyes that often are brightly coloured in life, sometimes with characteristic horizontal stripes, such as in Cestrotus species. Many species have variegated patterns on their wings, but in contrast they generally do not have variegated bodies, except for genera such as Cestrotus, whose camouflage mimics lichens or the texture of granitic rocks.
The Camillidae are a family of flies, or Diptera. The family has five genera.
The Megamerinidae are a family of flies (Diptera) with about 11 species in three genera. They are small and are marked by an elongated, basally constricted abdomen. The family has been variously placed in the past within the superfamilies Diopsoidea, Nerioidea and more recently in Opomyzoidea but the evolutionary relationships remain unclear.
Dipteran morphology differs in some significant ways from the broader morphology of insects. The Diptera is a very large and diverse order of mostly small to medium-sized insects. They have prominent compound eyes on a mobile head, and one pair of functional, membraneous wings, which are attached to a complex mesothorax. The second pair of wings, on the metathorax, are reduced to halteres. The order's fundamental peculiarity is its remarkable specialization in terms of wing shape and the morpho-anatomical adaptation of the thorax – features which lend particular agility to its flying forms. The filiform, stylate or aristate antennae correlate with the Nematocera, Brachycera and Cyclorrhapha taxa respectively. It displays substantial morphological uniformity in lower taxa, especially at the level of genus or species. The configuration of integumental bristles is of fundamental importance in their taxonomy, as is wing venation. It displays a complete metamorphosis, or holometabolous development. The larvae are legless, and have head capsules with mandibulate mouthparts in the Nematocera. The larvae of "higher flies" (Brachycera) are however headless and wormlike, and display only three instars. Pupae are obtect in the Nematocera, or coarcate in Brachycera.
The family Nothybidae contains only the genus Nothybus, a group of colorful and elongated flies. The family has been recently revised.
Fergusonina, the sole genus in the family of Fergusoninidae, are gall-forming flies. There are about 40 species in the genus, all of them producing galls on Eucalyptus, Melaleuca, Corymbia, and Metrosideros species in Australia and New Zealand.
Somatia is the sole genus of the acalyptrate brachyceran fly family Somatiidae. The genus includes about seven Neotropical species of small black and yellow flies with a stout and rounded thorax having transverse suture. The legs are separated from the main body by an elongated post-coxal bridge. The broad abdomen is downcurved. The antenna are elbowed with the arista bipectinate. Somatiids resemble members of the Syringogastridae due to the enlarged pronotum and a postcoxal bridge but they have a petiolate abdomen.
