Male
Head (Figs 3D, 4C). Face with distinct, low facial tubercle and with 3–4 grooves, black medially and yellow laterally, yellow pilose with seldom black pile on dorsal half and a shiny, bare median vitta, with dense pale pruinosity covering yellow lateral areas; gena yellow, with a small black macula at eye margin, yellow pilose with pale pruinosity dorsally; lunule black, with violet iridescence; frons black, with long black pile, shiny medially, with black pruinosity along eye margin (following pale pruinosity of face) and dorsally at eye angle; vertical triangle black, black pruinose, black pilose; antennal base inflated, protruded; antennal pits clearly separated; antenna elongated, black pilose, scape partly brown, pedicel and postpedicel black; postpedicel longer than scape and pedicel together; arista black, bare; eye almost bare, with a few scattered pile; occiput pale pruinose.
Thorax (Fig. 4B–C). Scutum black, densely pale pruinose, with long yellow and brown pile; postpronotum paler, bare, densely pale pruinose; postalar callus yellow; scutellum yellow, pale pruinose, mostly dark pilose with some pale pile on anterior and posterior margins, subscutellar fringe with long, yellow pile. Pleuron black except katatergum yellow, densely pale pruinose, yellow pilose; metaepisternum bare; metasternum bare; postmetacoxal bridge incomplete; calypter yellow, mostly yellow pilose, ventral calypter with brown fringe and fine erect pile on posterior part of dorsal surface; plumule long, pale; halter pedicel and capitulum yellow; posterior spiracular fringes yellow.
Wing. Hyaline, stigma yellow except dark brown basally; membrane bare basally, cells c, br and bm entirely bare, apical cells microtrichose but bare very basally; alula microtrichose.
Legs. Coxae and trochanters black, mostly yellow pilose; fore and mid femur yellow at base very narrowly and on apical half, darker basally; fore femur with long pile posteriorly, black apically and yellow basally; mid femur similar, but also with long pile anteriorly; fore and mid tibia yellow, yellow pilose; fore and mid tarsomeres yellow; hind coxa and hind trochanter with tuft of black pile medially; hind femur and hind tibia brown; hind femur with dense dorsal and ventral fringes of long pile, yellow on basal half and black on apical half; hind tibia with dense dorsal and ventral fringes of long black pile; hind tarsomeres pale.
Abdomen (Fig. 4B–C). Unmargined, narrowly oval, long pilose. Tergite 1 yellow, densely pale pruinose, yellow pilose; tergite 2 yellow on basal half and posterior margin, black on posterior half, with posterior margin yellow, pale pilose anteriorly and laterally, dark pilose medially on posterior half, densely pale pruinose; tergite 3 yellow on basal half, black on posterior half and on lateral margins, yellow pilose laterally and dark pilose medially, with some pale pile on anterior margin, densely pale pruinose, with two fasciate areas on posterior half less pruinose; tergite 4 black with a yellow fascia on posterior margin, with two medial yellow maculae on anterior half, yellow pilose laterally and dark pilose medially, densely pale pruinose, with two fasciate areas on posterior half less pruinose, smaller than on tergite 3; tergite 5 black, pruinose, black pilose. Sternite 1 yellow, with long yellow pile; sternites 2 and 3 yellow anteriorly and black posteriorly, with long yellow and black pile; sternite 4 black, long black pilose.
Male genitalia. As in Fig. 5F–H.
Female
Similar to male except normal sexual dimorphism and as specified in diagnosis.
Variation
Based on studied material, colouration of pile on scutum and scutellum may vary slightly in amount of dark pile, ranging from little to many.
Length (N = 4): body 12.7 mm (12.5–12.8 mm); wing 10.9 mm (10.8–11.0 mm).
unless otherwise stated