Stenopsocus aphidiformis Enderlein

(Figs. 5–6)

Stenopsocus aphidiformis Enderlein, 1906: 249 . Type locality: Japan (Kagoshima).

Diagnosis. This species is characterized by pale yellowish brown body (in alcohol), forewing with setae on Cu2 and transparent forewing without marking on the pterostigma. Living individual is green.

Adult male. Body (Fig. 5 a) length 2.75 mm, length from postclypeus to wing tip 5.15 mm. IO: 0.31 mm, d: 0.29 mm, IO/d=1.07, f1: 0.71 mm, f2: 0.66 mm, f3: 0.58 mm, FWL: 4.06 mm, FWW: 1.65 mm, HWL: 2.90 mm, HWW: 1.08 mm, t1: 0.43 mm, t2: 0.13 mm.

Colour (in alcohol). Body nearly whitish, Head (Figs. 5 c, d) with a brown marking around ocelli. Antenna brown. Mouthpart much paler, apex of maxillary palpus pale brownish, remaining segments of maxillary palpus whitish.

Thorax dorsally dark brown. Leg much paler, tibiae and tarsomeres of fore-leg pale brown. Abdomen whitish, genital segments with pale brownish, trichobothria area.

Forewings (Fig. 5 g) transparent and immaculate. All veins yellowish brown. Cu2 with single-row setae. Hindwing (Fig. 5 h) immaculate.

Genitalia (Figs. 6 a–d) slightly sclerotized. Epiproct (Fig. 6 b) subtriangular with a round apex. Paraproct (Fig. 6 a) with 36 trichobothria. Endophallus (Fig. 6 d) sclerotized, external parameres robust, with some punctures on broadened apex, exceeding apex of aedeagal arch; aedeagal arch narrow. Hypandrium (Fig. 6 c) slightly sclerotized.

Adult female. Body (Fig. 5 b) length 3.99 mm, length from postclypeus to wing tip 7.27 mm. IO: 0.52 mm, d: 0.23 mm, IO/d=2.26, f1: 1.12 mm, f2: 1.00 mm, f3: 0.75 mm, FWL: 5.93 mm, FWW: 1.96 mm, HWL: 4.24 mm, HWW: 1.35 mm, t1: 0.59 mm, t2: 0.19 mm.

Colour generally similar to male. Head (Figs. 5 e, f) with some brown markings on vertex and frontal area. Forewing and hindwing similar to male.

Genitalia (Figs. 6 e–i) slightly sclerotized. Epiproct (Fig. 6 f) subtrapezoidal with round apex. Paraproct (Fig. 6 e) with 44 trichobothria. Gonapophyses (Fig. 6 h) with external valve reduced, subtriangular, perpendicular to dorsal valve, ventral valve narrowly elongate, with acute apex. Subgenital plate (Fig. 6 g) slightly sclerotized.

Specimens examined. CHINA (TAIWAN): Hualien, Pi-lu Sacred Tree (2150 m), 2 males, 7.vi.2013, Liang Feiyang; Hualien, Dayuling, 1 female, 7.vi.2013, Luo Xingyu.

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

Remarks. This species differs from S. niger by the transparent and immaculate pterostigma.