Adiscus niger ( Chen, 1941 )

Duan, Wen-Yuan & Zhou, Hong-Zhang, 2022, Revision of the genus Adiscus Gistel, 1857 (Coleoptera: Chrysomelidae, Cryptocephalinae) from mainland China, Zootaxa 5096 (1), pp. 1-80 : 54-55

Adiscus niger ( Chen, 1941)

(Figs 22-1; 22-2)

Dioryctus niger Chen, 1941: 189 (type locality: Kweichow; type deposited: IZ-CAS).

Adiscus niger: Gressitt & Kimoto, 1961: 118 ; Schöller et al., 2010: 608 (catalogue).

Material examined. CHINA: Holotype: female, “ Guizhou / Chinese Academy of Sciences [Chinese letters] // HOLOTYPE ”. ( IZ-CAS) ; Additional material: Sichuan Province: 2 females, Luding Xingxin, 1800 m, 13. VI. 1983, coll. Shuyong Wang ( IZ-CAS) ; 1 female, Luding Xingxin, 2100 m, 5. VI. 1983, coll. Yuanqing Chen ( IZ-CAS) ; Gansu Province: 1 female, Wen country, Liujiaping, 1300–2100 m, 27. VI. 1998, coll. Jun Chen ( IZ-CAS) ; Shaanxi Province: 1 female, Liuba, Weituogou , 21. VII. 1998 ( IZ-CAS) ; Hubei Province: 1 female, Shennongjia, Jiuhuping, Chegou, 1600 m, 24. VII. 1998, coll, Xiaodong Yu ( IZ-CAS) ; 1 female, Shennongjia, Chegou, 1730 m, 4. VII. 1998, coll, Hongzhang Zhou ( IZ-CAS) .

Redescription. Measurements. Females. BL = 2.62–2.92 mm, BW = 2.98– 2.43 mm, HL = 0.86 mm, HW = 0.80 mm, PL = 0.72 mm, PW = 1.69 mm, PA = 100°, EL = 2.31 mm, EA = 160°, SL = 0.24 mm.

Body (Figs. 22-1; 22-2) small, dorsum black. Head black, apical half reddish brown; antennae and legs reddish brown.

Head shiny, finely and densely punctate. Eyes reniform, inner margin slightly emarginated; superior eye-lobes separated by greater distance than antennal insertions. Antennae absent in specimen studied.

Pronotum (Figs. 22-1; 22-2) broad, base much broader than apex, basal width about 2.3 times as long as pronotal length. Anterior margin nearly straight. Posterior slightly sinuate with fine serration, and its middle portion produced into an obtuse angle of about 100°. Disc evenly convex, slightly coarsely and rather closely punctures.

Elytra (Figs. 22-1; 22-2) as broad as prothorax at base, humeri somewhat prominent, glabrous. Disc finely punctate, with 11 regular striae, intervals with scattered minute punctures, puncture striae irregular on apical slope. Epipleural lobe (Fig. 22-2B) large, lateral margins weakly expanded ventrally and with slightly lobe at 1/3 of elytron, with both lobe sides forming angle of 160°, epipleura obliquely placed and visible in lateral view.

Venter clothed with short pubescence and fine punctures. Prosternum broad, trapezoidal, lateral margins extending outward, forming low longitudinal ridge. Mesoventrite twice as wide as long. Pygidium with dense punctures and short pubescence.

Female. Apical hollow in ventrite 5 deep and round. Spermatheca (Fig. 22-1D) f alcate, right-angled bending halfway, weakly acute at apex; duct not seen. Rectal sclerites (Figs. 22-1C) moderately sclerotized, sclerite slender, not connected between two rectangular sclerites on ventral side.

Distribution. China (Shaanxi, Hubei, Gansu, Sichuan, Guizhou).