Adiscus kweiyangensis ( Gressitt, 1942 )

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 : 44-47

Adiscus kweiyangensis ( Gressitt, 1942)

(Figs 18-1; 18-2)

Dioryctus kweiyangensis Gressitt, 1942: 334 (type locality: Kweiyang; type deposited: ICRI).

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

= Dioryctus monticolus Chûjô, 1954: 161 (type locality: Formosa); Kimoto, 1969: 5 (as synonym of Adiscus kweiyangensis ).

Material examined. CHINA: Hubei Province: 1 male, 1 female, Shennongjia, Songbai village , 4. VII. 1980, coll. Peiyu Yu ( IZ-CAS) ; 1 male, 44 females, Shennongjia, Songbai village , 5. VII. 1980, coll. Peiyu Yu ( IZ-CAS) ; 2 females, Shennongjia, Songluo , 13. VI. 1981, coll. Yinheng Han ( IZ-CAS) ; 1 female, Shennongjia, Songluo , 83. VI. 1981, coll. Yinheng Han ( IZ-CAS) ; 1 female, Hefeng watershed forest farm, 29. VII, 1989, coll. Shuyong Wang ( IZ-CAS) ; 1 female, Mt. Xing, Longmen river , 23. VI. 1993, coll. Hongxing Li ( IZ-CAS) ; Hunan Province: 1 female, Yongshun , 8. VIII. 1989, coll. Ningnian Xiao ( IZ-CAS) ; Sichuan Province: 1 male, Nanchong , 22. VI. 1981, coll. Huiming Luo ( IZ-CAS) ; 1 female, Wenchuan Wolong , 27. VII. 1983, coll. Shuyong Wang ( IZ-CAS) ; Guizhou Province: 21 males, Songtao , 2. VII. 1989, Ningnian Xiao ( IZ-CAS) .

Redescription. Measurements. Males. BL = 2.32–2.68 mm, BW = 1.69–1.94 mm, HL = 0.88 mm, HW = 0.79 mm, PL = 0.74 mm, PW = 1.68 mm, PA = 120°, EL = 1.97 mm, EA = 100°, AL = 1.35 mm, AW = 0.44 mm.

Females. BL = 2.64–2.96 mm, BW = 1..96– 2.24 mm, HL = 0.96 mm, HW = 0.86 mm, PL = 0.80 mm, PW = 1.83 mm, PA = 120°, EL = 2.14 mm, EA = 100°, SL = 0.28 mm.

Body (Figs. 18-1A; 18-2A) small and ovate. Head yellowish brown; apical region of mandibles black; antennae pale yellowish brown. Pronotum yellowish brown, and basal margin black. Elytra of the most common variety yellowish brown, with broad black transverse band along anterior margin, extending backward along lateral margin, and lateral middle region black and a large black spot on apical region, covering 1/3 area of elytra; scarcer variety black except transverse band on middle region of elytra yellowish brown. Legs yellowish brown, except claws black. Venter largely black, propleura, mesopleura and apical region of abdomen yellowish brown; basal region of pygidium black.

Head dull, with coarse punctures, and scattered minute punctures. Eyes reniform, superior eye-lobes separated by slightly greater distance than antennal insertions. Clypeus with denser and finer punctures than those on frons, densely and finely granulose, anterior margin arched and emarginated apically. Antennae short, reaching the humeral region of the elytra, scape swollen, clubbed, pedicel oblong, about half as long as scape, antennomeres 3 and 4 slender, 3 slightly shorter than 4, 5–11 slightly broadened and flattened, 3, 5 and 6 about equal in length, 7–10 slightly longer, each segment about equal in length, last segment pointed apically.

Pronotum (Figs. 18-1A; 18-2A) smooth, base much broader than apex, basal width about 2.3 times as long as pronotal length. Anterior margin nearly straight. Posterior margin undulated, and produced into an obtuse angle of about 120° at middle. Disc evenly convex, impunctate, glabrous.

Elytra (Figs. 18-1A; 18-2A) as broad as long, humeri somewhat prominent. Disc punctate, with 11 regular striae, intervals with scattered minute punctures, puncture striae irregular on apical slope. Epipleural lobe (Fig. 18-2B) large, lateral margins with coarser punctures than those on disc, and distinctly expanded ventrally with rounded lobe at basal 1/3 of elytron, with both lobe sides forming angle of 100°, epipleura obliquely placed and visible in lateral view.

Venter clothed with sparse short pubescence and fine punctures. Prosternal episternum finely rugose. Prosternum (Fig. 18-2C) trapezoidal, with dense coarse punctures, anterior margin arcuately concave, lateral margin elevated to a high longitudinal ridge, posterior margin nearly straight, hind angles slightly produced. Mesoventrite subtrapezoidal, with dense coarse punctures, anterior margin narrower than posterior one. Pygidium with dense coarse punctures. First segment of middle leg tarsus swollen.

Aedeagus. (Figs. 18-1D–F; 18-2D–F) Median lobe elongate, about 3 times as long as wide, middle part parallelsided. Apex of median lobe much narrower than middle, apex acute, strongly curved in lateral view; with dense long setae on each side of apex and median longitudinal line on ventral side of distal region, densely punctate on ventral side of distal part. Median orifice with median sclerite bending inwards below surface. Inner sac rather narrow, cylindrical, strongly narrowed at apical 1/4, base nearly round, but bilobed at apex. Tegmen Y-shaped, weakly sclerotized, almost translucent.

Female. Body more robust than in male, apical hollow in ventrite 5 deep and round. Spermatheca (Figs. 18-1C; 18-2G) falcate, nearly right-angled bending halfway, acute at apex, slightly dilated at 1/3 from apex, then extremely narrowed; duct weakly sclerotized, irregularly coiled. Rectal sclerites (Fig. 18-1G) weakly sclerotized, slightly connected between two rectangular sclerites on ventral side.

Distribution. China (Hubei, Hunnan, Sichuan, Guizhou, Taiwan).