Gergithus Stål, 1870

Meng, Rui & Wang, Yinglun, 2012, Two new species of the genus Gergithus Stål (Hemiptera: Fulgoromorpha: Issidae) from China, with a redescription of G. bimaculatus Zhang and Che, and G. tessellatus Matsumura, Zootaxa 3247, pp. 1-18 : 2

Gergithus Stål, 1870

Gergithus Stål, 1870: 756 . Type species: Hemispharius schaumi Stål , by original designation. Ishiharanus Hori, 1969: 58 . Type species: Gergithus iguchii Matsumura, 1916 , by original designation. Synonymised by Che et al., 2007: 611.

Description: The general characters of the genus below are mainly following Chan and Yang (1994) and Che et al. (2007), except the female genitalia.

Body hemispherical. Head including eyes narrower than pronotum. Vertex wider than long, disc depressed, without carina. Frons with disc slightly elevated, without median carina. Clypeus not angulate, always on same plane as frons. Rostrum long, reaching mesotrochanter or metatrochanter. Pronotum short and broad with two pits. Mesonotum triangular, disc slightly elevated. Tegmen elliptical, strongly convex and without claval suture, apical margin usually acutely rounded. Wing well-developed, reticulate, more than half length of tegmen. Legs relative long, lateral margin of hind tibia with two teeth. Spinal formula of hind leg (6–9)–(8–16)–2.

Male genitalia: Anal tube subtriangular, mushroom-shaped or cup-shaped. Suspensorium present. Pygofer in lateral view with hind margin roundly or spinously produced caudad medially. Aedeagus variable. Phallobase with dorsal lobe usually reflexed at apex. Genital styles in lateral view widening to apex. Capitulum of style in dorsal view with apex convex, apical margin with or without process, lateral margin with large lateral tooth.

Female genitalia: Sternum VII with middle of posterior margin clearly convex or concave. Anal tube nearly ovate in dorsal view, base wider than apex. Anal column short. Gonoplac slightly elevated in the median area, bor- der between first and second gonoplac lobes obsolete, third gonoplac lobes faintly sclerotized and pigmented, fork indistinct or distinct in dorsal view. Proximal part of posterior connective lamina of gonapophyses IX convex in lateral view, median field with notch in apical part. Gonocoxa VIII nearly rectangular, dorsal margin slightly protruding in proximal part. Endogonocoxal process narrowed to apex. Anterior connective lamina of gonapophysis VIII with three teeth in apical group and with two to four carinate teeth in lateral group.

Remarks: The genus Gergithus differs from the closely related Hemisphaerius Schaum by longer frons and legs, clypeus on the same plane of frons, and tegmina ovate ( Stål 1870). Melichar (1906) proposed that the genus differs from Hemisphaerius by the well-developed wings. Following the generic diagnosis from Chan and Yang (1994) and Che et al. (2007), this genus is distinguished within the Hemisphaeriini by frons without median carina; frons, pronotum and mesonotum without tubercles; and the wing longer than half the tegmen.

On the basis of the original description of “front darker along each side is adorned with a row of little yellow tubercles” and “fore-wings widened on the border at the base near which they are slightly concave” from Walker (1851), the placement of G. contusus Walker in Gergithus is doubtful; the species probably belongs in the genus Mongaliana Distant. Additionally, according to the description of “clypeus angulate” for G. signatifrons Melichar and G. lincolatus Melichar , and “frons with median carina” for G. cribratus Melichar from Melichar (1906), these three species should not belong to Gergithus . However, this conclusion can not be substantiated here as we have not examined any specimens.

For this reason, 56 species of Gergithus , including the two new species described here, are listed in the following key. The key is partly modified from Melichar (1906), Distant (1906), Matsumura (1916), Hori (1969), Chan and Yang (1994), and Che et al. (2007). Much of the key is based on the pattern and colouration of the frons and clypeus, which do not appear to vary between individuals within a species.