Differs from congeners in the combination of 2+1 dc, calypter with brown margin, black legs, and male abdomen with T2-5 brown microtomentose except for silvery microtomentose anterior half of T3-5 which is wider laterally.
Male coloration and vestiture: frons subshiny black, ocellar triangle and orbital plates subshiny black, lunule black, basoflagellomere black, face greyish microtomentose, palpus black; thorax with mesonotum brown microtomentose, scutellum and pleura same, except for shiny spots on anepisternum and katepisternum, wing hyaline, veins brown, brown spot at tip of vein R1 weak, calypter hyaline with brown margin (var.: light brown), halter black, legs black, hind tarsus with yellow brush (var. mid basitarsus yellowish); abdomen with T2-5 brown microtomentose except for silvery microtomentose anterior half of T3-5 which is wider laterally (var.: visible parts of T3-4 brown microtomentose except for silvery anterolateral margin of T3). Sometimes it appears as if there are two brown spots at posterior margin of T3-5.
Morphology. Head: frons with 2 orbital and 2+0.6 frontal setae, middle frontal seta medioclinate. In males frons 2.5x as wide at posterior margin than at base of antenna, arista about 3.7x as long as basoflagellomere wide, pubescence on arista very short, posterior eye margin with notch (5oc) and narrow emargination (1oc).
Thorax: 2+1 dc, 2 prsc, 1 pprn, 1+0.9 prs, 3 keps setae, posterior prsc about as long as posterior dc, seta between posterior prsc and posterior dc present. Wing with vein R4+5 and M1 converging (1.9), and ultimate section of vein M1 2.1x as long as penultimate section. Fore femur slightly stronger setulose, tibial organ absent.
Male abdomen: posteromedial triangular projection of T1 into T2 present. Tergal chaetotaxy: T2 anterolateral corner mostly with 2-5 lines of setae, T2-5 setulose on brown parts. S5 1.3x as long as wide, 1.8x as long and 1.4x as wide as S4, posterior margin indented, setulose. Male genitalia with apical seta on cercus as long as longest epandrial seta, 1 seta on subepandrial plate, surstylus 1.2x as long as epandrium high, bent posteriorly, dilated apically (2.4x), 7.8x as long as wide, structure of lateral surface smooth, medial surface with line of long setae near anterior margin.
Remarks. Variety with calypter margin light brown, mid basitarsus yellowish, and visible parts of T3-4 brown microtomentose except for silvery anterolateral margin of T3.
Body length: 3.1 mm; wing length: 3.1 mm.