''Platycheirus '' is a large

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

hoverflies Hoverflies, also called flower flies or syrphids, make up the insect family (biology), family Syrphidae. As their common name suggests, they are often seen Hover (behaviour), hovering or nectaring at flowers; the adults of many species feed main ...

. They are also called sedgesitters. The genus ''Platycheirus'' was established in 1828 by Lepeletier and Serville, with the type specimen of ''Syrphus scutatus'' Meigen. This genus is primarily

Holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

in distribution, encompassing 70 species within the

Nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America ...

region. Notably, at least 23 of these Nearctic species are also found in the

Palearctic realm The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. The ...

, with their approximately 110 species.The distribution of ''Platycheirus'' is markedly

boreal Boreal, northern, of the north. Derived from the name of the god of the north wind from Ancient Greek civilisation, Boreas (god), Boreas. It may also refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernand ...

, with half of the 70 Nearctic species in the Yukon, Northwest Territories, or Alaska. The genus is widespread from Mexico, Central and South America, Europe, Asia, Southeast Asia, ''Platycheirus'' are not found in Australia, Indonesia and New Guinea. The genus has a variety of food choices for larvae, ranging from generalized

aphid Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...

predators to species that specialize in feeding on one or two specific aphid species. Most are feeding within the ground layer of leaf litter.

Characteristics

For terminology and a key to European Syrphidae see Speight. ''Platycheirus'' are slender, small to medium-sized flies that are often covered in fine hairs. They are mostly black or metallic green, and they may have yellow, reddish, or whitish-yellow spots on their abdomens. These flies do not have any bristles. Platycheirus_brunnifrons_head_profile

The head of a ''Platycheirus'' is somewhat rounded and is usually a bit wider than it is tall. It is also slightly wider than the thorax, with a small indentation at the back. The epistoma, which is the lower part of the face, is black and has a central knob. The face is often slightly recessed and has a small bump. The upper edge of the mouth is slightly extended. Platycheirus wing diagram

The antennae are placed high on the face, above the middle, and the third segment of the antennae is longer than it is wide. The arista, which is a part of the antennae, is thickened in its base and has tiny hairs. The eyes are smooth and are holoptic in males, meaning they meet in the middle. The wings have a cross-vein (R-M) located before the middle of the discal cell. There is a distinct but not very strong spurious vein.

The legs of ''Platycheirus'' are somewhat slender. The hind metatarsi are thickened and show secondary sexual characteristics in males. This means that the front tibia and tarsi of males can be dilated in various ways and may have special colors. Sometimes, only the tarsi are dilated. Males can be identified by their legs, especially the front legs. Some females have unique markings that help with identification, but many females are harder to identify, and some may even be impossible to distinguish.

Species by subgenus

Subgenus: ''Carposcalis'' Enderlein, 1938

''Platycheirus'' alphabetic list

Diagnostic keys

Key to Nearctic ''Platycheirus''

Diptera fauna of New Zealand
ref name= miller21 />
Key to the ''platycheirus'' species of Taiwan plus DNA sequencing on 63 species.
ref name=steenis19 />
Key to "melanostomini" of the Neotropical region (1945, using outdated generic concept)
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A 1927 Key to North American species of males of the genus ''Platycheirus''
ref name= curranplaty />
Key to the insects to Russian Far East (''Platycheirus'' starts on page 363). In Russian
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The genus ''Platycheirus'' of Japan
ref name= ohara80 />
Description, keys and maps to the Nearctic species of ''Platycheirus''.
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List and short description of European species
ref name="Speight"/> Platycheirus.fulviventris.-.lindsey.jpg, '' Platycheirus fulviventris'' male Platycheirus peltatus (male).jpg, ''

Platycheirus peltatus ''Platycheirus peltatus'' is a Palearctic species of hoverfly. DescriptionExternal images
F ...

'' male Platycheirus.clypeatus.-.lindsey.jpg, ''

Platycheirus clypeatus ''Platycheirus clypeatus'' is a species of hoverfly. It is found across the Palearctic and in the Nearctic. The larvae feed on aphids. Adults are usually found on the edges of woodland or scrub, Heath (habitat), heath or along hedgerows where the ...

'' male Plat.manicatus.jpg, ''

Platycheirus manicatus ''Platycheirus manicatus'' is a species of hoverfly. It is found across the Palearctic and in Alaska. Description of malesPlatycheirus splendidus'' male Plat. albimanus.jpg, ''

Platycheirus albimanus ''Platycheirus albimanus'' is a common widespread species of hoverfly. A holarctic species its range includes Greenland, Iceland, Britain, mainland Europe, Russia, across Siberia to the pacific coast, the Philippines, Alaska Alaska ( ...

'' female Platycheirus manicatus (female).jpg, ''

Platycheirus manicatus ''Platycheirus manicatus'' is a species of hoverfly. It is found across the Palearctic and in Alaska. Description of males Platycheirus occultus ''Platycheirus occultus'' is a Palearctic species of hoverfly. DescriptionExternal images
...

'' female

References

{{Taxonbar, from=Q1756743 Hoverfly genera Diptera of Europe Hoverflies of North America Taxa named by Amédée Louis Michel le Peletier Taxa named by Jean Guillaume Audinet-Serville Syrphinae Bacchini