The Dixidae (meniscus

midge A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some mid ...

s) are a

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

of aquatic

nematocera The Nematocera (the name means "thread-horns") are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies but species from suborder Brachycera (the name means "sh ...

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 ...

(Diptera). The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e live in unpolluted, standing

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

s, just beneath the surface film, usually amongst marginal aquatic vegetation. They are found in all continents except Antarctica.

Description

For terms see

Morphology of Diptera 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 (at most) ...

Dixidae are small (body length not more than 5.0 mm) slender gnats with thin legs. The head is relatively broad. The antennae are thin and the flagellum has 14 segments. The proboscis is short and thick and the palpi are five-segmented. The thorax is slightly convex. The wing veins are without scales (with scales in the closely related family

Culicidae Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "litt ...

. The subcosta is fused with the costa at the level of the base of Rs or slightly proximal to this. The wing venation exhibits radial, medial, and cubital forks (R 4 branched, M 2 branched, Cu 2 branched). R 2+ 3 is strongly arched, the r–m crossvein is distinct, and the discal cell is absent. The anal vein of the wing is long. The genitalia of the male is inverted at 180° by torsion of segments 5–8.

Evolutionary history

The oldest known fossils of the group come from the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

of Asia, assigned to the extinct genera '' Syndixa'' and ''

Eucorethrina ''Eucorethrina'' is a genus of flies belonging to the family Chaoboridae Chaoboridae, commonly known as phantom midges or glassworms, is a family of fairly common midges with a cosmopolitan distribution. They are closely related to the Coret ...

,'' members of modern genera are not known until the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

References

External links

Delta Int Key
family description and image
BugGuideWing venationEOL
images
Diptera.info
images * Dixiidae in Italian Nematocera families {{Culicoidea-stub

Description

Evolutionary history

References

Further reading

External links