The species is separated by the slender posterolateral projection of the superior volsella and the lobate inferior volsella, the posterolateral weak lobes of the anal tergite, and the parallel-sided anal point.

Male imago (n=2). Total length 2.70−2.94 mm. Wing length 1.38−1.50 mm. Total length / wing length 1.96. Wing length / length of profemur 1.92−2.08.

Coloration. Thorax and legs dark brown. Abdomen with tergite I–V yellowish brown and tergite VI–VIII and hypopygium dark brown.

Head. AR 1.97−2.02. Ultimate flagellomere 590−600 mm long. Frontal tubercles absent. Temporal 13−15 setae, including 4 inner verticals, 5−6 outer verticals and 4−5 postorbitals. Clypeus with 13 setae. Tentorium 103−110 mm long, 28−30 mm wide. Palpomere lengths (in mm): 36−38, 38−40, 118−120, 140−145, 203−210. Palp segment 5^th / 3^rd 1.72−1.75.

Thorax. Antepronotals with 6−7 setae, dorsocentrals 8−10, acrostichals 8, prealars 3. Scutellum with 12−13 setae.

Wing (Fig. 1). VR 1.19−120, R with 16−18 setae, R₁ with 8−10 setae, R₄₊₅ with 10−11 setae. Brachiolum 2 setae. Squama with 2−3 setae.

Legs. Front tibia with 3 subapical setae, 113−120, 138−144 and 141−150 µm long, spurs of mid tibia 30−35 and 37−46 µm long excluding comb, comb with 32−36 teeth, 10 µm long; spurs of hind tibia 28−30 and 38−47 µm long excluding comb, comb with 42−48 teeth, 10−12 µm long. Ta₁ of mid legs with only 1 sensilla chaetica, sensilla chaetica absent in hind legs. Lengths (in µm) and proportions of legs as in Table 1.

Hypopygium (Figs 2−4). Tergite IX with weak lobes bearing 3−4 setae at each side of base of anal point. Laterosternite IX with 3 setae. Anal point 45−50 mm long, 5−6 mm wide, originating from caudal margin of anal tergite, completely parallel-side. Anal tergite bands Y-shaped. Phallapodeme 75−82 mm long. Transverse sternapodeme 56−60 mm long. Superior volsella (Fig. 4) slightly curved, with apical, partially sclerotized beak-like protrusion and slender spur-like posterolateral projection, bearing two long setae beside the beak-like protrusion, and covered with microtrichia in inner parts. Inferior volsella with a moderately blunt caudal projection, covered with microtrichia, and not reaching beyond margin of anal tergite. Gonocoxite 98−104 mm long, with 4 strong inner marginal setae. Gonostylus 168−175 mm long, slightly swollen at base, curved medially, moderately slender to apex, bearing 17−20 setae along inner margin. HR 0.58−0.59; HV 1.61−1.68.

Holotype ♂ (BDN No. 1291). CHINA: Hainan Province, Ledong Li Nationality Autonomous County, Jianfengling Nature Conservation area, 18°14'45.96"N, 109°30'42.69"E, 21.iv.1985, X. Wang. Paratype 1♂ (BDN No. 03578), same data as holotype.

From Latin exilis, slender, in reference to the slender posterolateral projections of superior volsella.

The species was collected in a subtropical mountain area in Hainan province in Oriental China.

China, Xinjiang Autonomous Region: 13♂♂, Kaba Altay, Baihualin Nature Conservation area, 48°03'39.05"N, 86°25'7.04"E, 15−16.vii.2002, Tang HQ, sweep net.

Based on Zorina (2001) and Yan et al. (2005), the species is easily distinguished from the other species of the genus by having shoulder-like posterior margin of tergite IX and digitiform superior volsella with a longitudinal keel.

This species is distributed in the Russian Far East and northwestern China.

The species can be separated by the blackish brown spots on thorax and legs, the distally swollen anal point and the gonostylus with basal weak expansion.

Male imago (n=2). Total length 3.13–3.60 mm. Wing length 1.50–1.88 mm. Total length / wing length 1.91–2.09. Wing length / length of profemur 2.05–2.14.

Coloration. Thorax (Fig. 5) yellowish brown, with median black brown vittae. Femur of front leg yellowish green with distal parts dark brown, tibia dark brown except for median parts yellowish green, tarsi dark brown with basal 3/4 of ta₁ yellowish green; femora and tibia of mid and hind legs yellowish green with distal parts of femora and basal parts of tibia dark brown, ta₁ to ta₅ lightly brown (Fig. 6). Abdomen yellowish green to brown, with tergite I–V yellowish green, tergite VI–VIII and hypopygium yellowish brown.

Head. AR 1.94–2.24. Ultimate flagellomere 620–760 mm long. Frontal tubercles absent. Temporal 13–15 setae, including 4–5 inner verticals, 4–6 outer verticals and 4–5 postorbitals. Clypeus with 13–21 setae. Tentorium 113–120 mm long, 27–37 mm wide. Palpomere lengths (in mm): 37–40, 39–45, 133–172, 133–158, 193–223. Palp segment 5^th / 3^rd 1.30–1.45.

Thorax. Antepronotum with 2 setae, dorsocentrals 8–10, acrostichals 4–7, prealars 4–5. Scutellum with 12–15 setae.

Wing (Fig. 7). VR 1.15–1.20, R with 12–16 setae, R₁ with 11–16 setae, R₄₊₅ with 18–25 setae. Brachiolum 2 setae. Squama with 3–4 setae.

Legs. Front tibia with 3 subapical setae, 113–135, 133–150 and 145–170 µm long, spurs of middle tibia 28–30 and 35–37 µm long excluding comb, comb with 22–34 teeth, 10–11 µm long; spurs of hind tibia 30–32 and 42–43 µm long excluding comb, comb with 34–45 teeth, 10–12 µm long. Sensilla chaetica of mid and hind legs absent. Lengths (in µm) and proportions of legs as in Table 2.

Hypopygium (Figs 8–10). Tergite IX with weak shoulder-like corners, bearing 13–20 setae at base of anal point. Laterosternite IX with 4–7 setae. Anal point originating from anterior of caudal margin of anal tergite in dorsal view, constricted basally, swollen apically, 43–50 mm long, 8–10 mm wide at base, 9–12 mm wide at apex. Anal tergite bands Y-shaped. Phallapodeme 68–80 mm long. Transverse sternapodeme 44–70 mm long. Superior volsella (Fig. 10) curved basally, straight distally, with large posterolateral projection, which is constricted medially forming a sharp angle, longitudinal membranous ridge present, bearing two long setae in distinct pits; covered with microtrichia in inner parts of superior volsella. Inferior volsella with reduced lobate caudal projection. Gonocoxite 85–100 mm long, with 4 strong inner marginal setae. Gonostylus 150–190 mm long, slightly swollen at base, concave medially, with rounded apex, bearing 8–20 setae along basal inner margin, and 10–14 setae along distal inner margin. HR 0.53–0.57; HV 1.89–2.09.

Holotype ♂ (BDN No. 04250). CHINA: Shaanxi Province, Baoji City, Feng County, Qinling, Dongyu, 33°54'42.03"N, 106°31'21.10"E, 30. vii. 1994, sweep net, W. Bu. Paratype (BDN No. 20598). CHINA: 1♂, Fujian Province, Jianning County, 26°49'51.25"N, 116°50'45.90"E, 25. ix. 2002, light trap, Z. Liu.

From Greek, melasma, spot, in reference to the dark brown spots on the thorax and legs.

The species is known from Palaearctic and Oriental China (Shaanxi Province; Fujian Province).

Male diagnosis: Based on the variation in Chinese material (Olecryptotendipes exilis sp. n., Olecryptotendipes melasmus sp. n.), the generic description given by Zorina (2007) should be emended as follows: “Antennal ratio 1.83–2.06” should be changed to “Antennal ratio 1.83–2.24”. “Total length 3.0–3.5 mm” should be emended to “Total length 2.7–3.6 mm.”

Based on the description and figures of Zorina (2003), posterior margin of tergite IX of Olecryptotendipes secundus not elongate but with caudolateral shoulders bearing 4 setae, which seem to Olecryptotendipes exilis sp. n. The gonostylus of Olecryptotendipes lenzi and Olecryptotendipes secundus nearly parallel-sided, but which is slender to apex of the two new species. The species Olecryptotendipes secundus only with sclerotized superior volsella and without membranous ridges, it seems to Olecryptotendipes exilis sp. n. with sclerotized beak-like protrusion. From the above, the generic characters of Olecryptotendipes should be emended as follows: “Posterior margin of tergite IX with caudolateral shoulders; gonostylus parallel-sided or slender to apex; superior volsella consisting of sclerotized part, dorsal and ventral setae present.”