Platycheirus flabella

Platycheirus flabella
Platycheirus flabella body male above female
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Family:	Syrphidae
Genus:	Platycheirus
Species:	P. flabella
Binomial name
Platycheirus flabella Hull, 1944

Platycheirus flabella, the smallspot sedgesitter, is a rare species of fly in the family Syrphidae. Found from mountainous regions of Alaska, Yukon Territory, British Columbia, Idaho, Washington, Ontario and Quebec, and Maine. P.flabella is similar to Platycheirus discimanus and Platycheirus thylax ^{[1] [2]}

Description of male

For terminology see Speight key to genera and glossary or Glossary of morphological terminology

Platycheirus flabella male legs front over middle

Length

6.8–9.1 mm (0.27–0.36 in)

Head

The vertex and front are shining black, while the face is somewhat densely covered in grey pollen, featuring a shining black tubercle and gena. The oral margin protrudes forward to the level of the tubercle.

Thorax

The scutellum and pleura are also shining black, with the sides of the scutellum and most of the pleura thinly dusted with white pubescence. Additionally, the pile of the scutellum is very long and sparse.

Abdomen

Moderately shining black, faintly greenish, becoming brassy on the lateral margin. On either side, and in the middle of the second segment there are small, oval, yellowish-brown spots separated from the lateral margin. There are similar spots upon the third and fourth segment lying close to the base of the segment. The pile of the abdomen is yellowish along the sides, short, appressed and black in the middles of the segments.

Legs (see figures)

The first fore tarsomere broadens evenly from base to apex, measuring 1.5 to 2 times as long as it is broad. The second fore tarsomere is variable in shape, rectangular, and can be up to 1.5 times as wide as it is long, approximately one-quarter the length of the first tarsomere. The remaining fore tarsomeres are unmodified. The fore femur features a ventral row of 4-6 stiff black setae (thick hairs) on its basal half. Additionally, there is a row of weak black posterior setae on the basal third of the fore tibia, while the other two-thirds of the tibia have setae that are three times as long. The mid femur has a ventral row of 5-7 weak black or white setae on its basal half. On the basal third of the mid tibia, there is a posteroventral row of 5-6 weak black setae on the apical half, which are approximately three times as long as the tibial diameter. ^{[1] [3] [4]}

• General Anatomy click to enlarge
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  Legs
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  Head
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  Wing
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  Bod

References

1. Young, Andrew D.; Marshall, Stephen A.; Skevington, Jeffrey H. (17 February 2016). "Revision of Platycheirus Lepeletier and Serville (Diptera: Syrphidae) in the Nearctic north of Mexico". Zootaxa. 4082 (1): 34. doi:10.11646/zootaxa.4082.1.1. ISSN   1175-5334. PMID   27394216.  This article incorporates textfrom this source, which is available under the CC BY 3.0 license.
2. Skevington, Jeffrey H.; Locke, Michelle M.; Young, Andrew D.; Moran, Kevin; et al. (2019). Field Guide to the Flower Flies of Northeastern North America. Princeton Field Guides. Princeton University Press. ISBN   9780691189406.
3. Hull, F. M (1944). "Some new forms of Platycheirus of the family Syrphidae". Bulletin of Th Brooklyn Entomological Society. 39: 75–79.
4. NIELSEN, TORE (2017). "A revision of and key to the Holarctic and Oriental Platycheirus manicatus group species (Diptera, Syrphidae)". Norwegian Journal of Entomology. 64: 28–52.