The Schizophora are a section of true flies containing 78 families, which are collectively referred to as muscoids, although technically the term "muscoid" should be limited to flies in the superfamily Muscoidea; this is an example of informal, historical usage persisting in the vernacular. The section is divided into two subsections, the Acalyptratae and Calyptratae, which are commonly referred to as acalyptrate muscoids and calyptrate muscoids, respectively.

The defining feature of the Schizophora is the presence of a special structure used to help the emerging adult fly break free of the puparium; this structure is an inflatable membranous sac called the ptilinum that protrudes from the face, above the antennae. The inflation of the ptilinum (using fluid hemolymph rather than air) creates pressure along the line of weakness in the puparium, which then bursts open along the seam to allow the adult to escape. When the adult emerges, the fluid is withdrawn, the ptilinum collapses, and the membrane retracts entirely back inside the head. The large, inverted, "U"-shaped suture in the face through which it came, however, is still quite visible, and the name "Schizophora" ("split-bearers") is derived from this ptilinal or frontal suture. The term was first used by Eduard Becher.

In contrast to eggs of other arthropods, most insect eggs are drought-resistant, because inside the maternal chorion, two additional membranes develop from embryonic tissue, the amnion and the serosa. This serosa secretes a cuticle rich in chitin that protects the embryo against desiccation. In the Schizophora, however, the serosa does not develop, but these flies lay their eggs in damp places, such as rotting organic matter.[1]

Marsh fly01
Marsh fly (Sciomyzidae)
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
(unranked): Cyclorrhapha
Section: Schizophora



  1. ^ Jacobs, C.G.; Rezende, G.L.; Lamers, G.E.; van der Zee, M. (2013). "The extraembryonic serosa protects the insect egg against desiccation". Proceedings of the Royal Society of London B: Biological Sciences. 280 (1764): 20131082. doi:10.1098/rspb.2013.1082. PMC 3712428. PMID 23782888.

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The Acalyptratae or Acalyptrata are a subsection of the Schizophora, which are a section of the order Diptera, the "true flies". In various contexts the Acalyptratae also are referred to informally as the acalyptrate muscoids, or acalyptrates, as opposed to the Calyptratae. All forms of the name refer to the lack of calypters in the members of this subsection of flies. An alternative name, Acalypterae is current, though in minority usage. It was first used by Justin Pierre Marie Macquart in 1835 for a section of his tribe Muscides; he used it to refer to all acalyptrates plus scathophagids and phorids, but excluding Conopidae.

The confusing forms of the names stem from their first usage; Acalyptratae and Acalyptrata actually are adjectival forms in New Latin. They were coined in the mid 19th century in contexts such as "Muscae Calyptratae and Acalyptratae" and "Diptera Acalyptrata", and the forms stuck.The Acalyptratae are a large assemblage, exhibiting very diverse habits, with one notable and perhaps surprising exception: no known acalyptrates are obligate blood-feeders (hematophagous), though blood feeding at various stages of the life history is common throughout other Dipteran sections.


Anthomyia is a genus of flies in the family Anthomyiidae. They look rather like small houseflies, but commonly have conspicuous black-and-white patterning. This appears to be a mild form of aposematic coloration, though they do not appear to be distasteful unless they have eaten something offensive to the predator and have loaded their guts with it.


Braulidae, or bee louse, is a family of fly (Diptera) with seven species in two genera, Braula and Megabraula. Found in honey bee colonies, these most unusual wingless and small flies, are not a true bee parasite, and are barely recognizable as Diptera, as they have the superficial appearance of mites or lice.


Calyptratae is a subsection of Schizophora in the insect order Diptera, commonly referred to as the calyptrate muscoids (or simply calyptrates). It consists of those flies which possess a calypter that covers the halteres, among which are some of the most familiar of all flies, such as the house fly.

About 18,000 described species are in this group, or about 12% of all the flies yet described.


Chyromyidae are small to very small cyclorrhaphous, acalypterate flies (Diptera) currently classified within the Heleomyzoidea by most authors. The majority have a pale yellow integument and bright iridescent green, red or purple eyes. The family is represented in all continents except Antarctica. There are about 150 named species in this family worldwide. There has been no comprehensive taxonomic study to elucidate the generic limits of species in the family. Currently, only four genera are recognised, but ongoing studies of the African species indicate that there are more.


Clusiidae or "druid flies" is a family of small (~ 3.5 mm), thin, yellow to black acalyptrate flies with a characteristic antenna (The second segment of the antennae has a triangular projection over the third segment when viewed from the outside) 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.


The Cryptochetidae are a small family of tiny flies (generally 2 to 4 mm long). Some twenty to thirty species are known. Generally they are metallic blue black, stoutly built, with the head broad and high and with clear wings. Like other species in the superfamily Lonchaeoidea, the Cryptochetidae have antennae with a cleft in the second segment. Unlike practically all Schizophora however, they lack an arista, or if they do have one, it is too small to distinguish with any confidence. The family name refers to this unusual distinction; "Cryptochetidae" literally means "those with hidden bristles". The adult flies also are unusual among insects in that they have only a single pair of abdominal spiracles — this is not a serious physiological challenge in such small insects.

Again in resemblance to other Lonchaeoidea, the Cryptochetidae do not have more than one proclinate orbital bristle on each side. The frons is densely setulose. The costa has a break at the end of the subcosta. The sixth abdominal sternite in the male is symmetrical and it has an 8th tergite. In the female the seventh tergite and sternite are fused, and the eighth segment is elongated.

The larvae are of biological and economic interest, being endoparasitoids of coccids. In Cryptochetum iceryae, which parasitizes Icerya, there are four larval instars. The first instar is sac-like and lacks both trophi and tracheae but at the caudal end it bears a pair of finger-like processes. The caudal end of the digestive tract is closed. During subsequent instars the caudal processes grow longer and become filamentous; in the final instar they are much longer than the whole body. These filaments probably are respiratory organs. Only a few species of Cryptochetidae have been described, and most of those occur in tropical countries. At one time they were allocated to the Agromyzidae but now are regarded as a separate family.


The Curtotonidae or quasimodo flies are a small family of small grey to dark brown humpbacked flies (Diptera) with a worldwide distribution, but with very few species in the Nearctic, Australasian/Oceanian, and Palaearctic regions. Most members of the family are found in tropical to subtropical latitudes in Africa and the Neotropics. Many remain undescribed in collections, since little work on the family has been done since the 1930s.


The Ephydroidea are a superfamily of muscomorph flies.


Homoneura is a genus of small flies of the family Lauxaniidae.


The Inbiomyiidae are a family of flies first described in 2006. 11 species have been described all in the genus Inbiomyia distributed in the Neotropical region. These are very small, mostly dark flies. The larval biology remains unknown.


The Lauxanioidea are a superfamily of flies that includes the two large families, the Lauxaniidae and Chamaemyiidae, and the small family Celyphidae. Generally, they are small to medium, densely populated, coloured flies. The Chamaemyiidae and Cremifaniidae live as parasites on insects. The family Celyphidae look like beetles.

Some authors also recognize the family Cremifaniidae, but most place this in the Chamaemyiidae.


The Megamerinidae are a family of flies (Diptera) with about 11 species in the genera Protexara Yang, Megamerina Rondani, and Texara Walker. They are marked by an elongated, basally constricted abdomen. The family is typically placed in the superfamily Diopsoidea (but may be placed in Nerioidea by some authors).


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 larvae of muscomorphs (in the sense the name is used here; see below) have reduced head capsules, and the pupae are formed inside the exoskeleton of the last larval instar; exit from this puparium is by a circular line of weakness, and this pupal type is called "cyclorrhaphous"; this feature gives this group of flies their traditional name, Cyclorrhapha.


The family Nothybidae contains only the genus Nothybus, a group of colorful and elongated flies. The family has been recently revised.


Oestroidea is a superfamily of Calyptratae including the blow flies, bot flies, flesh flies, and their relatives.The superfamily includes the families:


Mesembrinellidae (formerly included in Calliphoridae)



Rhiniidae (formerly included in Calliphoridae)






Sphaeroceroidea is a superfamily of flies. It includes the cosmopolitan families of Sphaeroceridae (small dung flies), Heleomyzidae, and Chyromyidae, as well as a few smaller groups.


The Tanypezidae, known as the “stretched-foot flies”, are small family of acalyptrate Diptera (Schizophora, Brachycera). The 28 species are found mostly in the New World, divided between two genera: Tanypeza (2 species) is found in North America, with the type species (T. longimana Fallén) extending into the Palaearctic, and Neotanypeza (26 species) is neotropical in distribution and includes one species known only from Dominican amber from 17–20 million years ago, N. dominicana Lonsdale & Apigian. This distribution contrasts that of its sister family, the Strongylophthalmyiidae, which is mostly East Asian in distribution.

The family was recently treated by Lonsdale (2013), who redefined the family and its genera, synonymizing all other neotropical tanypezid genera in Neotanypeza. Lonsdale (2014) also provided a full catalogue for the family.

Species of Tanypezidae are relatively large, and have semispherical heads and stout bodies that are perched atop long, thin legs, the latter of which have sometimes allied them with the families Neriidae and Micropezidae. The head and thorax are also often very dark with contrasting silver- (sometimes golden-) haired stripes and spots. Furthermore, apical convergence of wing veins R4+5 and M1 occurs, and no vibrissae, setulae on the upper surface of vein R1, and a large, flat “ocellar disc behind the ocelli. Little is known of the biology of tanypezid species, but T. longimana is known from low vegetation in humid deciduous woodlands, often around running water.

Theodor Becker

Theodor Becker (23 June 1840 in Plön – 30 June 1928 in Liegnitz) was a German civil engineer and entomologist primarily known for his work with flies.

He worked with Paul Stein, Mario Bezzi, and Kálmán Kertész on Katalog der Paläarktischen dipteren published in Budapest from 1903.

Extant Diptera families


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