Bioacoustics of Gymnogryllus

Description: Male. From lateral view, occiput wide; vertex inclined, shaped as spherical form with rostrum. Cheek slightly convex and much narrowed below eyes. Epistomal suture straight or curved upward in media. Fifth section of maxillary palpi always longer than third; the end section of labial palpi usually equal to the length of first two. Ocelli arranged in a straight line, media ocellus shaped as half-moon, lateral ocelli round or oval. Scape of antenna shield shaped. Frons always broad and flat, but partly narrow and concave below antennal socket. Top part of clypeus shaped as wide and flat stripe; lower part broad and flat, but slightly inclined inward. Labrum shaped as round shield, basal part somewhat concave medially, remaining part flat; distal edge straight or round in media. Pronotum broad. Median area with a straight groove, but short, always far from the posterior margin. Beside groove, a pair of crescent patterns, the color usually distinguished among different species. Pronotal anterior margin concave, posterior margin sinuated. Lower part of lateral lobes often in light color, but varied in size of different species. Lateral lobes covered in pubescence. Forewings do not reach tip of abdomen. Oblique veins two to three or four: outermost vein short, nearly vertical, but connects with Cu1; remainder of veins longer, arise from the base. Diagonal vein sinuate. Chord strongly bent. Two cross-veins between diagonal vein and chord, one of them free distally. Another cross-vein may or may not link chord with mirror. Mirror shaped as non-convex quadrilateral, its inner line always varies in different species. Mirror with one dividing vein. Apical field long, nearly half length of FWs. The apex of Cu1 with seven to ten inside branches, numbers varying by species. Stridulatory file feebly sinuate with inner margin armed with a cluster of long hairs. The distance between the file inner face and hairs varies by species. Teeth are mainly anvil-like with a few angular at the inside apex, sparse outside and medially, slightly dense from originating point of inside oblique vein inward apically. Hind wings longer than FWs. Foreleg thick; inner tympanum small and oval, outer one large and longer-oval shaped. Fore tibiae with three apical spurs; first section of fore tarsus smooth and bald, under first and second section with enlarged euplantula. Hind tibiae with five to six inner sub-apical spurs, five outer ones, and six apical spurs, both medial apical spurs of the two sides longer than others. Hind tarsus first section with short and thick spines along two sides dorsally, underneath with hard hair resembling thin spine. Cercus granulate, covered with dense sub-erect short hair and sparse long and thin hair. Epiproctum flat. Lamina subgenitalis hood-like in ventral view. Male genitalia robust, epiphallus shaped as half-tube in dorsal view and bulging distally; the distal section of epiphallus armed with a pair of long teeth; ectoparamere with widened distal part of large upper medial process and large proximal endoparameral apodeme. Ovipositor is relatively short and armed with a small hook before apical part of lower valvae.