Doryscus Jacoby

Lee, Chi-Feng, 2017, Revision of the genus Doryscus Jacoby (Coleoptera: Chrysomelidae: Galerucinae), Zootaxa 4269 (1), pp. 1-43 : 3

Genus Doryscus Jacoby

Doryscus Jacoby, 1887: 115 (type species: Doryscus testaceus Jacoby, 1887 , by monotypy); Jacoby, 1896a: 498; Jacoby, 1896b: 300; Maulik, 1936: 75; Chûjô, 1962: 16; Wilcox, 1973: 606; Seeno & Wilcox, 1982: 113; Kimoto, 1989: 9 (key); Kimoto & Takizawa, 1997: 298 (key); Medvedev & Sprecher-Uebersax, 2005: 318 (key); Beenen, 2010: 473; Yang et al., 2015: 287 (key).

Description. Body size small (length 3.4–6.5 mm), shape elongate oval, flattened. Head pale or black, sometimes pale with black strips along lateral margins of pronotum and elytra, and elytral suture; rarely pale with black elytra. Head. Labrum transverse, with rounded anterior angles, anterior margin slightly rounded, dorsally with few setigerous pores. Anterior part of head subtriangular, smooth, slightly convex, occiput wide and flat. Frontal tubercles subtriangular, with anterior angles divergent, basally separated from frons by impressed furrow. Interocular space wide, 1.9–2.4 times as wide as maximum diameter of eye. Interantennal space 1.0–1.4 times as wide as transverse diameter of antennal socket. Eyes small. Vertex wide, moderately convex, covered with several elongate setae. Antennae with 11 antennomeres, filiform, about 0.5–0.6 times as long as body, antennomere I swollen in males of some species.

Pronotum transverse; anterior and posterior margins broadly rounded, lateral margins rounded from anterior margin to posterior 1/3, strongly narrowed at posterior 1/3, subparallel from posterior 1/3 to posterior margin. Lateral and posterior margins narrowly bordered; all margins with sparse, elongate, erect setae; anterior and posterior margins with dense, short setae. Each angle bearing one setigerous pore and a long pale seta. Surface glabrous, indistinctly finely punctate, with a pair of distinct depressions laterally. Scutellum small, subtriangular.

Elytra flattened, parallel-sided, about 1.6–1.9 x longer than wide, with punctation dense, coarse, regularly arranged into longitudinal striae; and with dense, erect setae between punctures. Epipleura wide basally, gradually narrowed apically, and disappearing before apices. Humeral calli well developed. Macropterous.

Legs slender, apices of all tibiae with spines. First metatarsomere elongate triangular, ca. 1.3–1.4 as long as following two tarsomeres combined. Anterior and middle claws normal and appendiculate, posterior claws much larger, curved and not appendiculate. Procoxal cavities closed, intercoxal prosternal process narrow, elevated and visible between procoxae. Posterior margin of last ventrite with short distinct incisions.

Aedeagus slender, parallel-sided, apex of dorsal surface usually with deep notch, apex of ventral surface rounded or with shallow notch, endophallic sclerites with complicated spiculae differentiated between species.

Female. Abdomen with last ventrite entire or slightly depressed. Spermatheca variable in shape. Gonocoxae slender and fused together shortly at middle; each gonocoxa with nine setae along outer margin from apex to apical 1/3. Ventrite VIII usually square, usually with short setae along apical margin, with several elongate setae at sides; spiculum elongate

Diagnosis. Doryscus adults are similar to those of Strobiderus , Trichobalya , and Theopea with punctures on the elytra arranged into longitudinal striae and a pair of depressions on the sides of the pronotum. Members of Doryscus are easily recognized by their simple posterior claws, which are much longer in other genera.

Host plant. Adults of Doryscus chujoi were feeding on leaves of Lithocarpus kawakamii Hayata (Fagaceae) (present study).

Distribution. Oriental region, Nepal.