The Nymphomyiidae are a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of tiny (2 mm) slender, delicate

flies 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 m ...

(Diptera). Larvae are found among aquatic

moss Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and ...

es in small, rapid

stream A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long large streams ...

s 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 Archidiptera is a suborder of Diptera under an alternative classification based largely on fossil taxa; it has not gained wide acceptance among non-paleontological dipterists. Its sole living representative, the family Nymphomyiidae, is normall ...

(or Archaediptera) 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. The family Nymphomyiidae has several species which were originally placed in separate genera of their own. ''Nymphomyia alba'', the type species for this family, was discovered in a fast-flowing stream in Japan by

Masaaki Tokunaga Masaaki (written: , , , , , , , , , , , , , , , , , , , , , , , , , or ) is a masculine Japanese given name. Notable people with the name include: *, Japanese politician *, Japanese poet *, Japanese baseball player *, Japanese singer-songwriter * ...

in 1932. This was followed by ''Palaeodipteron walkeri'' described by Ide in Quebec in 1965 and ''Felicitomyia brundini'' was described from the Himalayas in 1970. Hennig examined the pupal characteristics of ''Nymphomyia'' and placed it in the family

Psychodidae Psychodidae, called drain flies, sink flies, filter flies, sewer flies, or sewer gnats, is a family of Fly, true flies. Some genera have short, hairy bodies and wings giving them a "furry" moth-like appearance, hence one of their common names, m ...

. Rohdendorf considered ''Nymphomyia'' so distinct that he put it in a separate superfamily Nymphomyioidea related to Triassic Dictyodipteridae which are in a suborder Archidiptera. Modern classifications put all the species in a single genus ''Nymphomyia''. Based on larval morphology, the family has been suggested to be close to the

Deuterophlebiidae The fly genus ''Deuterophlebia'' is the sole member of the small monogeneric family Deuterophlebiidae or mountain midges. Adults have broad, fan-shaped wings, and males have extremely long antennae which they employ when contesting territories ov ...

while others place them in a separate infraorder, the Nymphomyiomorpha. Nymphomyiidae are

neotenic Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compare ...

, retaining various larval features. They have strap-like wings with a very reduced venation, and the wing margins have long fringes like those of the Thysanoptera. The wings break at the base after mating. The antennae are very reduced. Species in the genus ''Nymphomyia'' have atrophied mouthparts. Nymphomyiidae are unusual in that the adults are ventrally holoptic, meaning they possess two eyes that meet on the underside of the head. Adults form large swarms above water. One or two generations may breed in a single year depending on the region and climate. Nymphomyiidae are thought to be closely related to the extinct

Strashilidae Strashilidae is an extinct family of Jurassic flies from Siberia and China. They were originally believed to represent a distinct order called Nakridletia, but subsequent research determined that they were nematoceran flies related to the ext ...

from the Jurassic of Asia, which are thought to have had a similar lifestyle.

Species

Currently all species are treated as members of a single genus: *'' Nymphomyia'' Tokunaga, 1932 **'' N. alba'' Tokunaga, 1932 - Japan **'' N. levanidovae'' Rohdendorf & Kalugina, 1974 - Siberia **'' N. brundini'' (Kevan, 1970) - Himalayas **'' N. holoptica'' Courtney 1994 - Hong Kong **'' N. rohdendorfi'' Makarchenko, 1979 - Siberia **'' N. walkeri'' (Ide, 1964) - Canada **'' Nymphomyia dolichopeza'' Courtney, 1994 - North America **'' Nymphomyia allissae'' (

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The ...

) **'' Nymphomyia succina'' (Baltic amber)

References

Nematocera families Blephariceromorpha {{Nematocera-stub