Lathrobium chengi Q.-H. Zhao and Peng, new species

(Figs 1A, 2)

Type material. HOLOTYPE: ♂, labeled ‘ China: Zhejiang Prov., Jingning County, Wangdongyang, 29°14'53''N 118°07'03''E, 1305 m, 17.VIII.2018, Cheng & Miao leg.’ (SNUC). Paratypes: 1 ♂, 2 ♀♀, same label data as holotype (SNUC).

Description. Measurements (in mm) and ratios: BL 8.95–9.12, FL 4.44–4.51, HL 1.14–1.16, HW 1.25–1.27, AnL 2.37–2.45, PL 1.60–1.65, PW 1.32–1.37, EL 0.91–0.96, AL 1.60–1.67, HL/HW 0.90–0.91, HW/PW 0.93–0.94, HL/PL 0.70–0.71, PL/PW 1.20–1.21, EL/PL 0.56–0.58.

Habitus as in Fig. 1A. Body dark brown with paler apex, legs brown, antennae brown to light brown.

Head: punctation moderately coarse and sparse, somewhat sparser in median dorsal portion; interstices with distinct microsculpture. Eyes moderately small and composed of approximately 70 ommatidia.

Pronotum parallel-sided; punctation somewhat sparser than that of head; impunctate midline broad; interstices without microsculpture.

Elytral punctation fine and moderately dense. Hind wings completely reduced. Protarsi with distinct sexual dimorphism.

Abdomen with fine and moderately dense punctation, that of tergite VII somewhat sparser than that of anterior tergites; interstices with shallow, but distinct microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII with weakly pronounced sexual dimorphism.

Male. Posterior margin of tergite VIII (Fig. 2D) nearly truncate; sternites III–IV unmodified; sternites III–IV unmodified; sternite V (Fig. 2A) with dark stout setae in large postero-median impression and at middle of posterior margin with cluster of numerous point-like setae; sternite VI (Fig. 2B) similar to sternite V, but with larger posteromedian impression and without point-like setae posteriorly; sternite VII (Fig. 2C) strongly transverse, without modified setae, posterior margin broadly concave; sternite VIII (Fig. 2E) transverse and nearly symmetric, with moderately extensive median impression posteriorly, this impression with numerous distinctly modified, stout blackish setae, posterior excision deeply concave; aedeagus as in Figs 2F–H; ventral process apically acute; dorsal plate with large apical portion and short basal portion; internal sac with three sclerotized spines of different shapes.

Female. Posterior margin of tergite VIII weakly convex; posterior margin of sternite VIII convexly produced.

Comparative notes. It resembles L. songi Peng & Q.-L. Li, 2015 from Baishanzu in Zhejiang in body size, the chaetotaxy of the male sternite VII, and the presence of three sclerotized spines in the internal sac of the aedeagus. Lathrobium chengi is distinguished from L. songi by the the chaetotaxy of the male sternite IV–VI, the deeper posterior excision of the male sternite VIII, the more slender ventral process of the aedeagus. For illustrations of L. songi see Peng et al. (2015: figures 6A, 7).

Distribution and natural history. The type locality is situated in aofoyan to the south of Jiangshan, southwestern Zhejiang. The specimens were sifted from leaf litter in a secondary pine forest at an altitude of 547 m.

Etymology. This species is dedicated to Mr. Zhi-Fei Cheng, who collected some of type specimens.