Male. Body length 7.5-8.0 mm Head. Eyes with dense and medium long ciliae, the longest cilia equal to the width of postpedicel； the narrowest of frons at least equal to anterior ocellus width； fronto-orbital plate adjoin in the middle, fr8 pairs on lower half of frons fronto-orbital plate, parafacial and gena with orange grey pruinosity； parafacial about 1.3 times as broad as postpedicel； antenna black, the length of postpedicel about 4.0 times as long as its width, arista long plumose, the longest hairs at least 1.5 times as long as the width of postpedicel； epistoma not protruding； vibrissal angle situated behind frontal angle； genal height about two-ninths to one-quarter of eye height； anterior margin of gena with 2 rows of upcurved setae, genal and postgenal setulae black； proboscis with pruinosity length of prementum about twice as long as height； palpus black, longer than cementum. Thorax. Ground-colour black, with orange grey pruinosity； scutum with 4 distinct black vittae. inner vitta reaching scutoscutellar suture, dorsal surface of scutellum with 1 distinct black vittae. about twice as broad as inner vitta of scutum:acr 0+1. dc2+4， ial 0+2， pra distinct, about a half to two-thirds length of posterior notopleural seta. notopleuron with hairs around posterior notopleural setae. lateral surface and ventral lateral margin of scutellum with black hairs, basisternum of prosternum and katepimeron all bare, meron with hairs； katepisternal setae 1（2）+2Wing. Transparent, veins brown, basicosta orange yellow, costal spine indistinct, radial node bare, R4+5 and M straight, cross-vein r-m slightly clouded； calypters yellowish, haltere yellow Legs. Completely black； fore tibia without median p； mid femur with pv row com plete, short and thin towards apex； mid tibia with 4 p； hind femur with av row complete, strong in apical half, the longest hairs about twice as long as the diameter of hind femur, without pv； middle part of hind tibia with 5-7 longer av, 7-8 ad in apical two-thirds, I row of longer and pectinate py（about 7-8）in basal four-fifths； tarsi longer than tibiae, claws and pulvilli medium long Abdomen. Ground-colour black, oval in dorsal view, with grey white pruinosity and shifting patches； tergites 3 and 4 each with a pair of subtrigonous and brown patches, tergites 3-5 without distinct median vittae, sternite I with hairs.