Stenopsocus niger Enderlein

(Figs. 7–8)

Stenopsocus niger Enderlein, 1906: 249. Type locality: Japan (Sapporo).

Diagnosis. This species has the large-sized body in the family Stenopsocidae. It is characterized by dark brown postclypeus (in alcohol), forewing with setae on Cu2 and transparent forewing with brown and thickened pterostigma. Living individual is orange.

Adult male. Body (Fig. 7 a) length 3.09 mm, length from postclypeus to wing tip 5.25 mm. IO: 0.38 mm, d: 0.26 mm, IO/d=1.46, f1: 1.08 mm, f2: 0.97 mm, f3: 0.74 mm, FWL: 4.42 mm, FWW: 1.53 mm, HWL: 3.16 mm, HWW: 1.04 mm, t1: 0.60 mm, t2: 0.16 mm.

Colour (in alcohol). Head (Figs. 7 c, d) brown, vertex with brown markings, a broad brown stripe present along epistomal stem to frontal area, cross ocellar area. Postclypeus blackish brown, labrum laterally brownish, 4th - segment of maxillary palpus dark brown, remaining segments of maxillary palpus yellowish.

Thorax dark brown. Leg yellowish, with coxae, tibiae, apices of 1st tarsomeres, and entire 2nd tarsomeres brownish; legs mostly brownish, with trochanter, part of femur whitish. Abdomen whitish. Genital segments pale brownish.

Forewings (Fig. 7 g) transparent. Veins brownish, an extremely narrow brown stripe along R, pterostigma brownish and thicken. Hindwing (Fig. 7 h) transparent, a narrow brown stripe between C and R.

Genitalia (Figs. 8 a–d) slightly sclerotized. Epiproct (Fig. 8 b) subtriangular with a round apex. Paraproct (Fig. 8 a) semi-sclerotized, with 33 trichobothria. Endophallus (Fig. 8 d) sclerotized, external parameres robust, with some punctures on broadened apex, not exceeding apex of aedeagal arch; aedeagal arch narrow. Hypandrium (Fig. 8 c) with a “V” shape sclerotized area.

Adult female. Body (Fig. 7 b) length 3.68 mm, length from postclypeus to wing tip 5.92 mm. IO: 0.50 mm, d: 0.22 mm, IO/d=2.27, f1: 0.77 mm, f2: 0.83 mm, f3: 0.63 mm, FWL: 4.96 mm, FWW: 1.61 mm, HWL: 3.51 mm, HWW: 1.11 mm, t1: 0.56 mm, t2: 0.17 mm.

Colour generally similar to male, but slightly darker.

Genitalia (Figs. 8 e–i) slightly sclerotized. Epiproct (Fig. 8 f) subtrapezoidal with round apex. Paraproct (Fig. 8 e) with 39 trichobothria. Gonapophyses (Fig. 8 h), external valve reduced, subtrapezoidal, with acute apex and nearly perpendicular to dorsal valve, ventral valve narrowly elongate, with acute apex. Subgenital plate (Fig. 8 g) with sclerotized area separated into two parts, a broad sclerotized area to connect two parts.

Specimens examined. CHINA (TAIWAN): Hualien, Pi-lu Sacred Tree (2150 m), 1 female, 7.vi.2013, Liang Feiyang; Taoyuan, Fuxing, 1 male, 1 female, 10.vi.2013, Liang Feiyang; Yilan, Fushan Nature Preserve, 1 female, 8.vi.2013, Luo Xingyu; Pingtung, Dahanshan, 2 males, 1 female, 2.vi.2013, Liang Feiyang

Distribution. China (Taiwan); Japan (Sapporo); Russian Far East.

Remarks. Enderlein (1906) described S. niger from Japan. Here is the firstly record from Taiwan, China. Both S. aphidiformis and S. niger can differ from the other four Taiwanese Stenospcous species by the forewing Cu2 with setae. This species differs from S. aphidiformis by the dark brown and thickened pterostigma and the brown legs.