Bioacoustics of Bucrates

Description (male except where specified) Head.— Fastigium of vertex 2 to 4 times as wide as scapus, blunt and as long as diameter of eye; fastigium of vertex touching fastigium of frons ( Fig. 14 H). Eyes small relative to size of head, weakly protruding. Frons weakly convex, smooth; tegumen of head smooth to weakly rugose, without traces of genal carinae; face slender to moderately broad. Mandibles and labrum weakly asymmetrical (right mandible smaller) ( Fig. 14 F). Thorax and wings.— Dorsal surface of pronotum smooth to moderately punctate, flat; both anterior and posterior dorsal margins straight; lateral lobes with posterior angle broadly rounded; humeral sinus well developed. Thoracic auditory spiracle large, elliptical, completely hidden under lateral lobe of pronotum; posterior edge of spiracle with small, finger-like projection. Prosternum armed with two thin, widely separated spines (modified basisternum); mesosternum with lateral lobes of basisterna triangular, their inner margins touching only at base; metasternal lobes touching along entire inner edge. Wings in both sexes either fully developed, well surpassing apices of hind femora or shortened, not reaching end of abdomen; tegmina slender to moderately wide. Stridulatory apparatus of male well developed; stridulatory area of left wing thickened, with dense network of secondary veinlets; stridulatory file (vein AA 1) straight to weakly curved ( Figs. 44 A-D), in some species stridulatory teeth strongly narrowed towards proximal (inner) end of file, and wider and thicker towards distal (outer) end of file; mirror of right wing oval or nearly circular. Posterior margin of tegmen weakly concave; apex of tegmen narrowly rounded. Species Fastigium Male cerci Male styli Stridulatory file capitatus 4 times as wide as scapus ( Fig. 13 F) teeth subapical ( Fig. 13 I) flattened dorso-ventrally ( Fig. 13 I) 3.2 mm proximal end evenly narrowing ( Fig. 42 A) clausus twice as wide as scapus ( Fig. 13 B) teeth apical ( Fig. 13 D) cylindrical ( Fig. 13 D) 2.8 mm proximal fourth strongly narrowed ( Fig. 42 D) Legs.— Fore coxa with an elongate, forward projecting spine dorsally; mid coxa with small, hook-like spine on upper margin. Fore and mid femora unarmed dorsally but armed ventrally on anterior margins; genicular lobes of fore femora unarmed, lobes of mid and hind femora armed with short spines, often only inner genicular lobes armed on mid femora . Fore and mid tibiae unarmed dorsally, both ventral margins with immovable spines as long as 1/4 to 1/2 diameter of tibia; hind tibia armed on all four dorsal and ventral margins; apex of tibia with two pairs of ventral and one pair of dorsal movable spurs; dorsal margins of hind tibia distinctly expanded laterally at apex. Tympanum on fore tibia bilaterally closed, tympanal slits facing forward, tympanal area only weakly swollen, with pair of small, elongated pits below tympanal slits. Abdomen.— Dorsal surface of abdominal terga smooth, unmodified. Male 10th tergite with shallow apical emargination, supraanal plate small, triangular. Male cercus with 2 apical or subapical spines, both bent inwards un- der right angle; upper spine 1/3 to 1/2 as long as lower spine; both spines with apices curved downwards when seen from behind; female cercus, simple, slender and weakly incurved. Subgenital plate of male with a pair of styli and small, triangular apical emargination; styli often strongly flattened dorso-ventrally; female subgenital plate triangular, with shallow apical emargination. Male concealed genitalia without well developed titillators, but with part of phallic membrane partially sclerotized and covered by chitinous callosities. Ovipositor narrow, weakly curved down; its length variable; both dorsal and ventral margins of ovipositor smooth, parallel; apex of upper valvula sharp, slightly thickened. Coloration.— Coloration grass green, olive green, or brown. Body dorsum usually with darker wide stripe, but often only lateral edges of pronotal dorsum with darker stripes. Tegmina frequently with numerous, dark speckles; stridulatory area of male tegmina often with darker edges.