Drabescus Stål 1870

Viraktamath, C. A., Webb, M. D. & Yeshwanth, H. M., 2022, Review of the leafhopper genus Drabescus Stål (Hemiptera: Cicadellidae: Deltocephalinae) in the Indian subcontinent with description of one new species, Zootaxa 5128 (2), pp. 225-247 : 226-227

Genus Drabescus Stål 1870

Selenocephalus (Drabescus) Stål 1870: 738 . Type species: Bythoscopus remotus Walker , by monotypy.

Tylissus Stål 1870: 739 . Type species: Tylissus nitens Stål , by monotypy.

Paradrabescus Kuoh 1985: 379 . Type species: Paradrabescus testaceus Kuoh , by original designation.

Drabescus (Leucostigmidium) Anufriev & Emeljanov 1988: 174 . Type species: Selenocephalus nigrifemoratus Matsumura , by original designation.

Drabescus (Ochrescus) Anufriev & Emeljanov 1988: 175 . Type species: Drabescus ochrifrons Vilbaste , by original designation.

Diagnosis. Medium sized (6.5–10.5 mm long), robust arboreal leafhoppers with fore margin of head transversely striate or carinate, sometimes rimmed, rarely smooth, epistomal suture sometimes carinate; crown short, more than 4× as wide between eyes as long medially. Face including eyes wider than long, lateral frontal sutures extending to ocelli, antennal ledges well developed sometimes encroaching onto clypeus, antennal bases placed closer to anterior eye angle than to posterior eye angle, antennae in adults about as long as or longer than head width, but in nymphs longer; clypeus longitudinally striate or rugose; clypellus widened apically. Pronotum more than 2× as wide as long medially, produced anteriorly to anterior angles of eyes and rarely beyond; disc slightly convex, transversely striate, narrower than head and shorter than exposed mesonotum. Forewing claval veins either connected by a cross vein or not, appendix large. Fore femur with hair-like setae on row AV, intercalary setae hair-like either in one row or scattered, row AM with AM1 only; fore tibia flattened and often expanded, with dorsal margins strongly carinate. Hind femur macrosetae 2+1. Male pygofer without anterior apodemes, longer than basal height in lateral view, with or without macrosetae, with or without ventral spine-like process, basolateral membranous cleft present. Subgenital plates free, triangular, apex narrowed, appendage-like, without macrosetae. Style with or without subapical lobe. Connective Y-shaped. Aedeagus with or without basal processes on shaft, gonopore subapical to apical on ventral surface. Female sternite VII wider than long with posterior margin variously produced medially or excavated medially in the form of V. Female valvula I convex, dorsal sculpturing pattern strigate, reaching dorsal margin. Valvula II with dorsal median tooth, teeth on apical 0.33 or more.

Remarks. Drabescus contains more than 60 species from the Afrotropical, Palaearctic, Oriental and Australian regions. Its species are very variable but Zhang & Webb (1996) cautioned that “the characters give contradictory evidence of relationship” and thus synonymized some genera and refrained from establishing new genera for the included species “until the many new species seen are described and a detailed study of all the species is undertaken.” This character variation is very evident in the small number of species dealt with here from the Indian subcontinent. Of the eight species in this study three, D. limbaticeps , D. shillongensis and D. stramineus have a white or pale yellow anterior border on the pronotum variably margined by dark brown, this pale border at the lateral extremity bends posteriorly along the submargin and is margined by prominent dark brown laterally ( Figs. 2 EF, 4AB). The remaining five species lack such a pale border. The male pygofer in D. angulatus , D. conspicuus , D. nervosopunctatus , D. nigrofacialis and D. shillongensis is terminated by a ventral spine like process that exceeds apex of the pygofer; on the other hand, in D. austroindicus sp. nov. and D. kempi , the pygofer lacks a ventral process, but the ventral margin is concave with a series of 3–5 denticles. With the exception of D. nigrofacialis , all the species from the Indian subcontinent (where males are known) have a pair of basal lateral processes on the aedeagal shaft.

Figures

FIGURES 2 A–L. Species of Drabescus from Indian subcontinent. Habitus, dorsal and lateral views (A–F) and female sternite VII (G–L). A–B, D. nervosopunctatus Signoret; C–D, D. nigrofacialis (Distant); E–F, D. shillongensis Rao; G, D. angulatus Signoret; H, D. kempi Pruthi; I, D. limbaticeps Signoret; J, D. nervosopunctatus Signoret; K, D. nigrofacialis (Distant); L, D. shillongensis Rao.