Male. Head black in ground color, anterior portion of gena reddish; epistoma yellowish interfrontal area black; parafrontal and upper 1/2 of parafacial densely yellow or golden yellow pollinose; lower portion of parafacial, face and gena densely whitish pollinose; upper portion of occiput with greyish pollinosity; lower portion of occiput whitish grey pollinose; antenna black, inside of 3rd segment narrowly reddish yellow on its base; arista brown-black. Vertex 0.20-0.21 of head width; interfrontal area widened anteriorly, subequal in width to parafrontal at middle parafacial weakly narrowed below, 1.5-2.0× as wide as 3rd antennal segment at middle; gena 0.27-0.28 of eye- height; occiput rather flattened. Inner vertical seta about 0.5 of eye-height; outer vertical seta indistinct; 2 fine and long postocellar setae; 1 fine and long postvertical seta on each side; 2-3 reclinate orbital setae, which are slightly shorter than ocellar seta; ocellar seta subequal in length to inner vertical seta; 10-13 inclinate and proclinate frontal setae, lowest one inserted at a level with base of arista; vibrissa strong, vibrissal insertion conspicuously above lower margin of face（by a distance subequal in length to 2nd antennal segment）; parafrontal with a rather regular row of very fine black hairs along row of frontal setae; gena sparsely clothed with very fine hairs. Antenna with 2nd segment 0.33× as long as 3rd; 3rd segment 0.27-0.28× as wide as long and falling short of lower margin of face by about 1/2 of its length. Arista longer than antenna, 2nd segment shorter than wide; 3rd segment thickened on its basal 1/5. Palpus nearly cylin-drical, subequal in length to 3rd antennal segment. Thorax, including scutellum, black in ground color; dorsum with dense yellowish pollinosity pleuron thinly greyish white pollinose; dorsum of prescutum with 4 longitudinal vittae; scutum with 5 longitudinal vittae, median 3 vittae fused on anterior portion. Hairs on dorsum dense fine and short, on pleuron longer, on scutellum rather strong and erect; 3+3 dc; 4 humeral setae 3 basal ones set in a straight line, middle one of them weakest; 1+1 stpl; 6-8 hypopleural setae basal scutellar seta 2.3-2.5×as long as scutellum; subapical scutellar seta subequal in length to basal one; apical scutellar seta absent; preapical scutellar seta suberect, about 1.5x as long as scutellum; distance between 2 subapical scutellar setae about 0.5× as long as that between basal and subapical ones of same side. Wing hyaline, weakly tinged with brown on its anterior portion and along veins; veins brown calypter pale brownish white; halter pale brownish yellow. Second costal sector about 0.4× as long as 3rd, and subequal in length to 4th; length of vein M, from discal crossvein to its bend about 0.67× as long as that from the bend to apex of vein Mi, and about 1.3× as long as distance be- tween the bend and wing margin; discal crossvein weakly curved; ultimate section of vein M3 about 0.6x as long as discal crossvein. Second costal sector with fine hairs on its ventral side; 4th costal sector setulose on its basal 1/4-1/5 Legs black, trochanters reddish brown; pulvilli pale brownish yellow. Mid-leg strongly elongate, mid-tibia weakly sinuate; mid-tarsus 15-1.7× as long as mid-tibia; fore claw and pul- villus longer than 5th tarsomere. Fore tibia with 1 strong p seta; mid-tibia with 1 very fine, some times indistinct, ad, 2 strong pd and 1 very fine, sometimes indistinct, v setae:hind tibia with a row of ad, 2-4 pd and 2-3 v setae; 2 preapical d setae on hind tibia. Abdomen black in ground color, anterolateral portion of 3rd tergum reddish; dorsum of an-terior 1/2 of 3rd and 4th terga and anterior 1/3 of 5th tergum densely clothed with pale yellowish white pollinosity; mid-dorsal longitudinal vitta distinct on 3rd to 5th terga; venter of 3rd and 4th terga thinly clothed with greyish white pollinosity; venter of 5th tergum with greyish white pol- linosity only on its narrow anterior margin. Abdomen narrow and elongate in shape, subequal in length to combined length of head and thorax; mid-dorsal excavation of syntergum 1+2 extending to median marginal setae; 3rd tergum slightly shorter than 4th, and almost 1.3× as long as 5th; Sth tergum conical, gradually narrowed to apex. hairs on dorsum erect and rather sparse on venter sparse and suberect; venter of 5th tergum with very dense and long hair-fascicle; 2nd tergum with 1 strong lateromarginal seta and 2 strong median marginal setae; 3rd tergum with 1 strong laterodiscal and 1 strong lateromarginal setae on each side and with 2 pairs of median discal and 2 strong median marginal setae; 4th tergum with 1 strong laterodiscal seta on each side and with 2 pairs of median discal and a row of strong marginal setae; 5th tergum with rows of strong discal and marginal setae; anterior pair of discal setae on 3rd and 4th terga weaker than posterior pair; 5th sternum parallel-sided, posterior lobe with dense and long hairs; 6th tergum strongly narrowed at middle, without hair. Male genitalia:In dorsal view cerci narrowly separated from each other at middle and approximated at apex, in lateral view rather broad and weakly curved dorsally at apex; surstylus very slightly longer than cercus, in lateral view rather broad, with dense fine hairs; basiphallus with broad dorsal process; pregonite narrow and long, with several hairs on its posterior margin and with a strong inwardly curved seta on its apex. Female. Unknown Body length：8.8-11.6 mm, wing length：6.5-7.6 mm