Hexarhopalus (Hexarhopalus) liuyixiaoi Jiang, Bai, Ren & Wang sp. nov.

(Figs 1–2, 21B, 22 A–D)

Type material (52 spec., 35 ♂♂, 17 ♀♀). Holotype: CHINA: ♂, labeled ‘ China: Hunan, Yueyang City, Pingjiang County (Ṭűss), Fushoushan (ŠƦƜẁdǔǡ), 28°28’N, 113°46’ E, 1079 m, 20.IX.2016, Jiang, Liu & Zhou leg.’ (MHBU) . Paratypes: CHINA: 34 ♂♂, 17 ♀♀. 14 ♂♂, 7 ♀♀, same label data as the holotype (1 ♂, 1 ♀ MYNU; 2 ♂♂, 2 ♀♀ QUST; 5 ♂♂, 2 ♀♀ SHNU; 6 ♂♂, 2 ♀♀ MHBU). 20 ♂♂, 10 ♀♀, labeled ‘ China, Hubei, Xianning City (ŘŤḿ), Tongshan Hsien (áƜss), Jiugong Shan (ŁŽƜ) , 29°23’32”N, 114°39’07”E, 1530 m, 30.VII-02.VIII.2016, Hu & Liu leg.’ (10 ♂♂, 5 ♀♀ SHNU; 8 ♂♂, 3 ♀♀ MHBU; 2 ♂♂, 2 ♀♀ LPCB) .

Description. Male (Figs 1A, 2 A–G). Body more slender than female, long oval, convex, black dull-shiny. Head (Fig. 2A) transverse. Vertex finely covered with small punctures and short hairs. Genae and clypeus covered with denser punctures and hairs. Labrum narrower than clypeus, covered with bristles of medium length in apical portion. Antennal tubercles slightly prominent, antenna (Fig. 2B) nearly as long as head and pronotum combined, club loosely formed by apical four antennomeres. Antennomere I slightly expanded; II shortest, about as long as wide; III longest, more than three times as II, IV-VII similar, shorter than II, apical four dark brown, longer than wide, XI with rounded apex.

Pronotum (Fig. 2A) slightly wider than long, widest near middle, dorsal surface finely covered with small punctures and short hairs. Margins of pronotum with deep groove around, groove W-shaped on anterior part. Middle suture shallow, broadened at base, with pair of obvious depressions in middle area on both sides of the median line.

Elytra ovoid, nearly twice as long as wide, shoulders strongly narrowed, widest at apical 1/3, disc with regular rows of strongly foveolate punctures, scutellum transverse, near triangular. Hind wings completely reduced.

Femora obviously claviform at middle, all tibiae covered with brown setae at apex, protibiae and mesotibiae slightly curved, metatibiae straight.

Aedeagus (Figs 2 C–E) nearly symmetrical. Abdominal ventrite VIII (Fig. 2F) deeply split medially at posterior margin and with long dense hairs. Spiculum gastrale (Fig. 2G) dissymmetrical, short, with large apical lobes.

Measurements. AnL 6.28–6.58 mm, BL 15.94–16.24 mm, HL 2.51–2.55 mm, HW 2.92–3.19 mm, PL 3.98–4.19 mm, PW 4.05–4.30 mm, EL 9.45–10.50 mm, EW 5.23–6.25 mm, AL 2.17 mm.

Female (Fig. 1B), similar to males, but usually larger. Ventrite VIII (Fig. 2H) slightly split medially at posterior margin and covered with long dense hair. Spiculum (Fig. 2H) tortuous at middle, apex rounded and slightly dilated. Apex of ovipositor (Fig. 2I) with one long hair and two much shorter hairs.

Measurements. AnL 6.24–6.64 mm, BL 15.96–19.47 mm, HL 2.50–3.00 mm, HW 2.86–3.42 mm, PL 3.82–4.69 mm, PW 3.92–4.72 mm, EL 9.64–11.78 mm, EW 5.73–6.72 mm.

Comparative Notes. The new species can be easily differentiated from its congeners by the distinctive groove on the pronotum uninterrupted and W-shaped on the anterior part.

Distribution. China: Hunan, Hubei.

Biology. The adults of this new species can be collected on tree trunks at night (Figs 22 A–D).

Etymology. This species is named in honor of the first author’s colleague Mr. Yi-Xiao Liu, who collected the new species and worked with the first author together for three years.