Adapted from Doesburg (1955).
MALE.
Head: Eyes relatively small, broadly separated, with long white pile. Vertex bluish black, separated from the front by a groovy line; ocellar triangle equilateral, with long pili, white and black intermingled. Frontal triangle rather coarsely punctured; front and face covered by silvery-white pollinosity, which conceals the black ground-colour. A broad fascia along the inner eyeborder, a space above the base of antennae, as well as two vittae, connected with the lunule and running down over the face are glossy black. With the exception of these glossy/shiny parts, face and front are provided with very long, scattered pili. Facial tubercle low, nose-like; the extreme point black and glossy. Gena with a very broad and deep pollinosity, running down from the lower eye-border to the oral opening. Occiput with very long pile. Behind the eye is a row of black, overhanging bristles. Antennae black, pedicel short, basoflagellomere enormously elongated, stretching beyond the facial knob, covered with dark-yellow pollinosity. Arista stout yellow, subbasal.
Thorax: Scutum and scutellum bluish black, glossy, provided with coarse, scattered punctures and very long, mostly white, erected pile. These pile are scarce on the scutum, abundant and somewhat curled at the sides and on the pleura. Legs black. Profemur thickened towards the base, decreasing to the thin apex; there are very long, white pili behind; at the base a tuft of thick, stiff, black bristles and towards the apex a group of dark, curled and curved pili, decreasing in length to the apex. Protibia scarcely dilated in the middle and at the apex, with long, white pile behind, to the tip mingled with still longer, black pili. First protarsomere much enlarged, silvery glossy, with three black vittae of dust; second tarsomere white, dilated, short; the remaining tarsomeres common, black. Mesofemur somewhat less thickened than the profemur, for the rest mesofemur and mesotibia of the same shape. First mesotarsomere long, nearly as long as the remaining tarsomeres together. Mesofemur and tibia with long, white pile behind. Metafemur and metatibia about of the same shape as in the mesoleg. Metatarsus elongated, nearly 1.5 times as long as tibia; metatarsus strongly thickened; metafemur and metatibia with long pile behind; these pili are white on femur, black, much longer and somewhat stronger, on the tibia. Wings hyaline, stigma yellow. Calypter whitish, halteres brownish.
Abdomen: ovate, dull black with long, white pile, longest on the venter and at the sides of the base. Terga 2-5 with a pair of bluish silvery pollinose maculae on athe anterior half, broadening towards the lateral margins. Hypopygium black, rather large. Venter black, the esterna with yellow brown posterior borders.
FEMALE.
Like the male, but differing in the following: vertex very broad; antennae a little thicker; the groove between vertex and front shallower; legs without enlargements and the pile all white.
Platycheirus (Pseudoplatychirus) peteri (Doesburg, 1955).
Doesburg, P.H. van 1955. Report on the syrphid flies, collected by the "Fourth Dutch Karakorum Expedition, 1935 (Mededelingen over Syrphidae XIII). Beaufortia 5, 47-51. [1955.09.09]
Pseudoplatychirus was described as a new genus by Doesburg (1955), but Thompson and Rotheray (1998), in the Manual of Palaearctic Diptera, considered it as a subgenus of Platycheirus.
unless otherwise stated