Holotype: ♂, China, Shaanxi, Nanzheng county, Beiba town, 20.vi.2005, Yi-Bin Ba leg. (MHBU).

This new species is similar to Stenochinus cylindricus (Gebien, 1914), but can be distinguished from the latter by the pronotum moderately projecting anteriorly, with emargination in middle of anterior margin; scutellum subrectangular; maxillary palpomere IV strongly expanded (in Stenochinus cylindricus, pronotum strongly projecting anteriorly, without emargination at anterior margin (Figs 4, 6); scutellum subquadrate; maxillary palpomere IV moderately expanded). It also resembles Stenochinus wakoi Masumoto & Akita, 2002, but differs in the following characters: antennomeres VIII–XI wider than long; pronotum with emargination in middle of anterior margin; scutellum subrectangular, glabrous (in Stenochinus wakoi, antennomeres VI–XI wider than long; pronotum without emargination at anterior margin; scutellum subquadrate, covered with scale-like hairs on both sides).

Figures 1−6.

Pronotum. 1 Stenochinus apiciconcavus sp. n. 2−3, 5 Stenochinus xinyicus sp. n. (2, 5 ♂ 3 ♀) 4, 6 Stenochinus cylindricus. Scale bars = 0.5 mm.

The specific name is derived from the Latin apici [apex] + concavus[concave], a reference to the pronotum with an emargination in middle of anterior margin.

Male (Fig. 17). Body length 10.3 mm, elongate, subcylindrical. Head, elytra and legs dark reddish brown, antennae reddish brown, pronotum dark brown. Scale-like hairs on the surface pale golden. Head transversely subelliptical, surface densely punctate; clypeus truncate at anterior margin, clypeogenal suture grooved, frontoclypeal suture invisible; genae weakly raised, with rounded outer margins; frons wide, distance between eyes 2.56 times as wide as transverse diameter of an eye in dorsal view. Eyes medium-sized, weakly protruding, each side with a groove along inner and posterior margins. Antennae (Fig. 7) clavate, antennomeres VIII–XI each wider than long, antennomeres XI ovate, ratio of the length of antennomeres II–XI as 0.12 : 0.18 : 0.09 : 0.09 : 0.07 : 0.08 : 0.07 : 0.10 : 0.08 : 0.22. Maxillary palpomere IV strongly expanded. Pronotum (Fig. 1) 1.13 times as long as wide, widest in middle; anterior margin with a distinct emargination in middle; posterior margin weakly bisinuate, with deep emargination in middle; both sides steeply inclined downward, lateral margins sinuate before posterior angles; anterior angles acute and directed anteriad, posterior angles acute and directed postero-laterad; disc subelliptically projecting in anterior parts, this projecting area distinctly impressed, surface roughly and deeply punctuate, punctures often fused with one anonther. Scutellum subrectangular, glabrous. Elytra 2.5 times as long as wide, widest at apical 1/3, 2.76 times as long as and 1.25 times as wide as pronotum; dorsum convex but flattened in lateral view; disc with rows of subquadrate punctures, which are larger and deeper anteriorly, each puncture with a granule on each lateral margin; intervals somewhat transversely wrinkled, weakly ridged in lateral parts, scale-like hairs on the intervals shorter than those on pronotum. Ventral side covered with dense punctures and scale-like hairs, which distinctly shorter than those on pronotum. Legs relatively short, ratio of the lengths of metatarsomeres I–IV as 0.45 : 0.24 : 0.17 : 0.69. Male genitalia (Figs 11–12) curved in middle in lateral view, 1.94 mm long, 0.43 mm wide; apicale 0.71 mm long, weakly curved in lateral view.

Figures 7−16.

7−10 Antennae 11−16 Male genitalia in dorsal view and lateral view 7, 11−12 Stenochinus apiciconcavus sp. n. 8−9, 13−14 Stenochinus xinyicus sp. n. (8 ♂ 9 ♀) 10, 15−16 Stenochinus cylindricus. Scale bars = 0.5 mm

Figures 17−20.

Habitus. 17 Stenochinus apiciconcavus sp. n. ♂ 18−19 Stenochinus xinyicus sp. n. (18 ♂ 19 ♀) 20 Stenochinus cylindricus ♂.

Female: Unknown.

Holotype: ♂, China, Guangdong, Xinyi City, Dawuling, 1.vi.2002, Cheng Chen leg. (MHBU). Paratypes: 3 ♀♀, same locality as holotype, 31.v.2002, Zhong-Ping Deng leg.; 1.vi.2002, Cui-Feng Li leg.; 6.vii.1988, Feng-Long Jia leg. (MHBU); 2 ♀♀, same locality as holotype, 31.v.2002, Bing-Lan Zhang leg.; 7.vii.1988, He-Xiang Zhou leg. (SYSU).

This new species is similar to Stenochinus cylindricus, but can be distinguished from the latter by antennomeres VII–XI wider than long, pronotum moderately projecting anteriorly (Fig. 5), shape of male genitalia different (Figs 13–16) (in Stenochinus cylindricus, antennomeres VIII–XI wider than long (Fig. 10), pronotum strongly projecting anteriorly (Fig. 6)).

The specific name is derived from the type locality of this species.

Male (Fig. 18). Body length 11.0 mm, elongate, subcylindrical. Head, elytra, legs reddish brown, pronotum brown, antennae and mouthparts yellowish brown; scale-like hairs surface pale golden. Head transversely subelliptical, surface densely punctate; clypeus transverse, weakly convex in middle, clypeogenal suture grooved, frontoclypeal suture invisible; genae weakly raised; frons wide, distance between eyes 2.53 times as wide as the transverse diameter of an eye in dorsal view. Eyes medium-sized, weakly protruding, with groove along inner and posterior margins. Antennae (Fig. 8) clavate, antennomeres VII–XI wider than long, antennomeres XI oval, length ratio of antennomeres II–XI as 0.16 : 0.17 : 0.12 : 0.10 : 0.09 : 0.09 : 0.10 : 0.13 : 0.10 : 0.23. Maxillary palpomere IV moderately expanded. Pronotum (Fig. 2) 1.14 times as long as wide, widest shortly before middle; anterior margin weakly reflexed; posterior margin weakly bisinuate, with deep emargination in middle; both sides steeply inclined downward, lateral margins sinuate before posterior angles; anterior angles acute and directed anteriorly, posterior angles obtuse and directed posteriorly; disc subelliptically projected in anterior parts, projecting area weakly impressed, surface roughly and deeply punctuate, punctures often fused with another. Scutellum subquadrate, glabrous. Elytra 2.51 times as long as wide, widest at apical 1/3, 2.80 times as long as and 1.11 times as wide as pronotum; dorsum convex but flattened in lateral view; disc with rows of large, deep and subquadrate punctures, each puncture with a granule on each lateral margin; intervals somewhat transversely wrinkled, scale-like hairs shorter and narrower than those on pronotum. Ventral side covered with dense punctures and scale-like hairs, which shorter than those on pronotum. Legs relatively short, length ratio of metatarsomeres I–IV as 0.40 : 0.33 : 0.21 : 0.67. Male genitalia (Figs 13–14) strongly curved in middle in lateral view, 2.29 mm long, 0.43 mm wide; apicale 0.77 mm long, weakly curved in lateral view.

Female (Fig. 19): Body 11.0–12.5 mm, dark brown. Antennae (Fig. 9) thicker, length ratio of antennomeres II–XI as 0.12 : 0.14 : 0.11 : 0.10 : 0.07 : 0.08 : 0.09 : 0.12 : 0.11 : 0.26. Pronotum (Fig. 3) 1.10 times as long as wide. Elytra 2.42 times as long as wide.

2 ♂♂, 5 unsexed, China, Taiwan, Hualien county, Xiulin township, Tailuge, 60–500 m, 13.v.2010, Wen-Yi Zhou leg. (MHBU); 1 unsexed, China, Taiwan, Taitung city, Lianren town, Shouka, 450 m, 16.vi.2010, Wen-Yi Zhou leg. (MHBU).

South China: Taiwan.

Holotype: ♂, China, Guangxi, Fangcheng, Fulong, 500 m, 24.v.1999, Da-Jun Liu leg. (IZCAS).

South China: Guangxi.