CHINA: Hainan Prov.: Holotype: ♀, Mt. Diaoluoshan, alt. 1040 m, 24.V.1999, J. R. Fellowes leg. (cRou). Other material: 42♂♂, 30♀♀, Mt. Diaoluoshan, Diaoluozhandao, alt. 930–1000 m, 20–23.IV.2010, YIN Zi-Wei, FENG Ting & YUAN Xiao-Zhuan leg. (1♂, 1♀ in cPut, remainder in SHNU).

Male. Sternite VII (Fig. 9) impressed in posteromedian portion with emargination along posterior margin of impression, impression densely setose; sternite VIII (Fig. 10) with a triangular emargination at middle of posterior margin, length of the emargination about 1/ 5 of total length along the midline; sternite IX (Fig. 11) with long and slightly acute apicolateral projections, posterior margin nearly straight; tergite X (Fig. 12) with posterior margin truncate. Median lobe of aedeagus (Fig. 13) broad near base and tapering apicad, apex of median lobe (Fig. 14) forming an acute projection with two pairs of short setae; parameres (Fig. 14) slightly longer than median lobe, swollen at apex, each with about 14 to 15 setae on apico-internal margins.

The duct of the spermatheca may be folded to different degrees (Figs 18–21).

China (Hainan Province: Diaoluoshan).

CHINA: Guangdong Prov.: Holotype: ♂, Ruyuan County, Nanling Nature Reserve, alt. 1019 m, 18.VI.2007, HUANG Hao & XU Wang leg. (SHNU). Other material: 1♂, Ruyuan County, Nanling Nature Reserve, alt. 1500–1800 m, 17.VIII.2008, QI Nan & YIN Zi-Wei leg. (SHNU); 2♀♀, Ruyuan County, Nanling Nature Reserve, alt. 1100 m, 14.VIII.2008, QI Nan & YIN Zi-Wei leg. (SHNU); 1♂, Shaoguan City, Nanling Nature Reserve, alt. 700 m, 18.VIII.2010, TANG Liang leg. (SHNU).

Female. Sternite VIII (Fig. 27) with posterior margin indistinctly prominent in the middle; tergite X (Fig. 28) with posterior margin broadly rounded and slightly emarginated at apex; valvifers (Fig. 29) each with big tooth at apex, posterior margin serrate; strongly sclerotized spermatheca very simple (Fig. 30).

In the original description, the elytral mark of the species was described as obsolete. In fact, there is an indistinct elongate orange mark in the lateral portion of each elytron (Fig. 3).

China (Guangdong Province: Nanling).

Holotype: CHINA: Guangxi Prov.: ♂, Lingui County, Huaping Nature Reserve, Anjiangping, alt. 1400–1700 m, 14.VII.2011, PENG Zhong leg. (SHNU). Paratypes: CHINA: Guangxi Prov.: 4♂♂, 7♀♀, Lingui County, Huaping Nature Reserve, Anjiangping, alt. 1300–1700 m, 14–18.VII.2011, TANG Liang , HE Wen-Jia & PENG Zhong leg. (1♂, 1♀ in cPut, remainder in SHNU).

BL: 3.5–3.9 mm; FL: 1.6–1.8 mm.

HW: 0.72–0.79 mm, PW: 0.53–0.55 mm, PL: 0.55–0.60 mm, EW: 0.60–0.68 mm, EL: 0.59–0.66 mm, SL: 0.44–0.49 mm.

Brachypterous; body brownish except for the blackish head, anterior margin of labrum, antennae, maxillary palpi and legs yellowish brown, each elytron with an elongate ill-defined orange mark near lateral side, this mark 1/3 to 1/2 as long and about 1/3 to 2/5 as broad as the respective elytron.

Head 1.16–1.21 times as wide as elytra; interocular area with two broad longitudinal furrows, median portion convex dorsally, not reaching level of inner eye margins; punctation round and slightly confluent, uniform except for several large punctures at posterior part of median portion; diameter of large punctures about as wide as antennal segment II in cross-section, interstices between punctures smooth, mostly narrower than half the diameter of punctures, those along midline much wider, forming a broad impunctate line. Relative length of antennal segments from base to apex 12: 9: 20: 11: 10.5: 10.5: 9: 6.5: 7: 8: 10.5. Paraglossae oval.

Pronotum 1.05–1.09 times as long as wide, 0.81–0.88 times as wide as elytra; disk with shallow median longitudinal furrow about 1/2 the length of pronotum; punctures round and moderately confluent, smaller in size than largest punctures on head, interstices smooth, narrower than half the diameter of punctures.

Elytra 0.96–0.98 times as long as wide, distinctly constricted at base, lateral margins gently divergent posteriad; disk almost even; punctures round to elliptic, uniform, slightly coarser than those of pronotum, interstices smooth, narrower than half the diameter of punctures.

Legs with hind tarsi 0.72–0.78 times as long as hind tibiae, tarsomere IV strongly bilobed.

Abdomen cylindrical; paratergites very narrow and smooth, present only at abdominal segment III, tergite VII with indistinct palisade fringe; punctation of tergite III–VIII sparse and shallow, gradually becoming finer posteriad, interstices smooth, varying from narrower to much wider than diameter of punctures.

Male. Sternite VII with shallow emargination at middle of posterior margin and a depression before it; sternite VIII (Fig. 31) with semi-circular emargination at middle of posterior margin; sternite IX (Fig. 32) with long apicolateral projections, posterior margin serrate; tergite X (Fig. 33) with posterior margin convex. Aedeagus (Fig. 34) with apical sclerotized portion of median lobe pointed at apex; expulsion hooks (Fig. 36) very large; parameres longer than median lobe, slightly swollen at apex, each with about 14 short setae at apico-internal margins.

Female. Sternite VIII (Fig. 37) with posterior margin entire; tergite X (Fig. 38) with posterior margin convex. Valvifers (Fig. 39) each with large apicolateral tooth; sclerotized spermatheca as in Fig. 40.

China (Guangxi Province: Huaping).

The new species resembles Stenus huanghaoi Tang & Li, 2008, with which it shares the faint elytral marks, but it may be distinguished by the heterogeneous punctation of the frons (in Stenus huanghaoi always similar in size), the shallower pronotal punctation (especially in the median furrow) and smaller body size (in Stenus huanghaoi BL: 3.9–4.5 mm).

This species is named in honor of Mr. Zhang Ding-Heng, administrator of the Huaping Nature Reserve, who provided help in various ways during our field work.

All the specimens were collected by sifting the leaves of bamboo and broad-leaved shrubs in a thick forest (Fig. 50).

Holotype: CHINA: Guangxi Prov.: ♂, Xing’an County, Mt. Mao’ershan, alt. 2100 m, 10.VII.2011, TANG Liang & HE Wen-Jia leg. (SHNU). Paratype: CHINA: Guangxi Prov.: 1♀, same data as holotype. (SHNU).

BL: 4.3 mm; FL: 2.0 mm.

HW: 0.81–0.82 mm, PW: 0.60–0.61 mm, PL: 0.63–0.64 mm, EW: 0.76 mm, EL:0.71–0.72 mm, SL: 0.54–0.55 mm.

Brachypterous; body brownish black, head darker, anterior margin of labrum, antennae, maxillary palpi and legs yellowish brown, each elytron with a large elongate orange mark near lateral margin, this mark 4/5 as long as and about 3/5 as broad as the respective elytron.

Head 1.07–1.08 times as wide as elytra; interocular area with two broad longitudinal furrows, median portion convex, almost reaching the level of inner eye margins; punctures round, slightly larger and sparser in median area than those near inner margins of eyes, diameter of large punctures as wide as apical cross section of antennal segment II, interstices between punctures smooth, mostly narrower than half the diameter of punctures, those along midline a little wider. Relative length of antennal segments from base to apex 15: 9: 24: 14: 12: 9.5: 9.5: 6.5: 7: 8: 10. Paraglossae oval.

Pronotum 1.04–1.05 times as long as wide, 0.80–0.81 times as wide as elytra; disk with distinct median longitudinal furrow, this furrow about half the length of pronotum; punctation round and confluent, similar to that of head, interstices smooth, much narrower than half the diameter of punctures except for those in median furrow, which may be wider.

Elytra 0.94–0.95 times as long as wide, distinctly constricted at base, lateral margins gently divergent posteriad; punctation similar to that of pronotum, but slightly coarser, interstices similar to those of pronotum.

Legs with hind tarsi 0.74–0.75 times as long as hind tibiae, tarsomere IV strongly bilobed.

Abdomen cylindrical; paratergites very narrow and smooth, present only in abdominal segment III, posterior margin of tergite VII with indistinct palisade fringe; punctation of tergite III–VIII sparse and shallow, gradually becoming finer posteriad, interstices smooth, varying from narrower to much wider than diameter of punctures.

Male. Sternite VII with inconspicuous emargination at middle of posterior margin, anterior to this emargination flattened; sternite VIII (Fig. 41) with semi-circular emargination at middle of posterior margin; sternite IX (Fig. 42) with long apicolateral projections, posterior margin serrate; tergite X (Fig. 43) with posterior margin truncate and slightly emarginated at middle. Aedeagus (Fig. 44) with apical sclerotized portion of median lobe triangular; expulsion hooks absent (probably lost in this specimen); parameres longer than median lobe, each with 8–9 setae on apico-internal margins.

Female. Sternite VIII (Fig. 46) inconspicuously prominent at middle of posterior margin; tergite X (Fig. 47) with posterior margin truncate and slightly emarginated at middle. Valvifers (Fig. 48) each with big apicolateral tooth; spermatheca strongly sclerotized (Fig. 49).

China (Guangxi Province: Mao’ershan).

The new species resembles Stenus nanlingmotis Tang & Li, 2008 from Guangdong, but may be distinguished by the broader and deeper pronotal furrow with wider interstices, which may be as wide as diameter of punctures (in Stenus nanlingmotis smaller than half the diameter of punctures); the elytral marks are broader, about 3/5 as broad as the respective elytron (in Stenus nanlingmotis about 2/5 as broad as the respective elytron).

The specific name is derived from “Mao’ershan”, the type locality of this species.

The female specimen was collected by sifting the leaves of bamboo and broad-leaved shrubs near the mountain summit, the male specimen was collected by beating grass along a drain exposed in sunshine.