Stenopsocus wangi sp. nov.

(Figs. 4–5)

Diagnosis. This species is characterized by the dark brown vertex, yellowish pedicel, r-rs without marking and largely sclerotized female subgenital plate.

Female. Measurements. Body length 2.78 mm, length from postclypeus to wing tip 4.30 mm. IO: 0.54 mm, d: 0.17 mm, IO/d = 3.18, f1: 0.89 mm, f2: 0.70 mm, FWL: 3.22 mm, FWW: 0.95 mm, HWL: 2.39 mm, HWW: 0.66 mm, t1: 0.34 mm, t2: 0.11 mm.

Coloration (in alcohol). Head (Fig. 4 b–d) dark brown except mouthparts. Antennal scape and flagellum dark brown, pedicel yellowish white. Mouthparts yellowish white, with dark brown postclypeus, labral base yellowish, base of maxillary palp dark brown. Prothorax dark purplish brown, meso- and metathorax dark brown. Legs mostly yellowish white, tip of femora and tarsomere 2 brown. Forewing (Fig. 4 e) transparent, wing margin mostly brown, anterior margin of pterostigma yellowish; R dark brown, branch of R and Rs surrounded by a brown marking, a brown stripe present along R 1 in pterostigma. Hind wing (Fig. 4 f) transparent, with a slightly brown marking between costal vein and R. Abdomen dorsally dark purple, genital segments blackish brown.

Genitalia (Fig. 5 a) distinctly sclerotized. Epiproct (Fig. 5 b) subtriangular. Paraproct entirely sclerotized, with 22 trichobothrias. Subgenital plate (Fig. 5 c) mostly sclerotized, lateral sclerotized region darker than middle one. Gonapophyses (Fig. 5 d) distinctly sclerotized, external valve subtriangular, dorsal and ventral valve blade-shaped. Male. Unknown.

Type material. Holotype female, Laos: Oudomxai, Park Beng, 350 m, 25.III.2016, Xinyue Liu (CAU) . Paratype: 1 female, Laos: Oudomxai, near Muang Xai, 880 m, 24.III.2016, Xingyue Liu (CAU) .

Distribution. Laos (Oudomxai).

Etymology. The new species is dedicated to Dr. Guoquan Wang for his kind help during the field trip in Laos.

Remarks. This new species appears to be closely related to Stenopsocus eucallus Li & Yang, 1988 (China), Stenopsocus formosanus Banks, 1937 (China) and Stenopsocus signatipennis New, 1978 (Nepal) in having similar forewing marking patterns, but it can be distinguished from the latter three species by the dark brown vertex, yellowish pedicel and largely sclerotized subgenital plate. In S. eucallus, S. formosanus and S. signatipennis, the vertex and pedicel are yellowish, and the middle of female subgenital plate sclerotize indistinctly (Banks 1937; Li 2002; Liang et al., 2015; New 1978). It is necessary to examine more materials to distinguish the latter three species.