Bioacoustics of Borneogryllacris sakaerat

Description. Medium sized species. Head: Face ovoid; forehead in middle with fine riffles, laterally nearly smooth; fastigium verticis distinctly wider than scapus; ocelli distinct; fastigium frontis separated from fastigium verticis by a very fine suture; subocular furrows shallow ( Fig. 48N ). Abdominal tergites two and three with few largely reduced, indistinct, not easily visible stridulatory pegs. Wings: Tegmen strongly shortened, surpassing tip of first abdominal tergite but not reaching tip of second tergite ( Fig. 47 K–L). Tegmen: venation strongly reduced. Legs: Fore coxa with a spine at fore margin; fore and mid femora unarmed; fore and mid tibiae with four pairs of large ventral spines and one pair of smaller ventral spurs; hind femur with 2–6 external and 3–7 internal spines on ventral margins; hind tibia with spaced spines on both dorsal margins, ventral margins without pre-apical spines, only with 3 apical spurs on both sides. Coloration. Strikingly colored; dorsally with alternating black and yellow bands and red head; legs medium brown, on underside yellow brown ( Figs. 100E , 101A ). Face uniformly red brown, ocelli and a spot on clypeus yellow. Tegmen black with a yellow spot at base; a small circle in mid-length and at tip yellowish semi-transparent; hind wing shorter than and hidden under fore wings. Male. Eighth abdominal tergite not much longer than seventh. Ninth abdominal tergite globular, black, with a light brown furrow in midline, at apex on both sides of furrow with a small yellow swelling followed by a long, black, compressed, acute spine ( Fig. 50E ). Paraproctes forming extended plates from base of cerci, narrowing and overlapping each other in midline. Subgenital plate wider than long with a slight depression in middle, lateral margin convex, apical margin concave; stout, conical and slightly curved styli inserted at apico-lateral angles. Female. Seventh abdominal sternite of normal shape but with apical margin faintly concave in middle. Intersegmental membrane between seventh sternite and subgenital plate strongly prolonged; sclerotised part of subgenital plate forming an elevated half-ring with hind margin concave in middle, only laterally it extends as a small band along to about half of that membranous area ( Fig. 51E ). With a small sclerite before base of ovipositor. Ovipositor elongate, substraight, with slightly converging margins; before tip margins more strongly narrowing, tip subobtuse ( Fig. 51F ). Measurements ( 1 male , 3 females ).—body w/o wings: male 30, female 31–33; pronotum: male 5.5, female 6.0–6.5; tegmen: male 7.5, female 7–9; hind femur: male 16.5, female 16.5–17.0; antenna: female 80; ovipositor: female 19.5–22.0 mm.

Description of female. Medium large, brachypterous species ( Fig. 47J ). Head: Face ovoid; forehead nearly smooth with scattered impressed dots, in ventral area rather matt and with fine transverse riffles; fastigium verticis wider than scapus; ocelli distinct, yellowish white; fastigium frontis separated from fastigium verticis by a very fine suture; subocular furrows indistinct ( Fig. 48J ). Abdominal tergites two and three without stridulatory pegs. Wings reaching to and partly covering fourth abdominal tergite. Coloration. General color yellowish brown, head and legs reddish brown; pronotum with black rim and black bands along fore- and hind margins; abdominal tergites yellowish brown with black band along hind margin; abdominal sternites black on both sides with yellowish brown midline and apical area. Face red brown except for ivory white ocelli. Tegmen yellowish at base; semi-transparent along fore margin and in apical area; otherwise covered by a large black spot surrounding a yellowish spot in middle. Male. See description in Gorochov et al . 2015. Female. Seventh abdominal sternite as sixth sternite with hind margin roundly projecting in middle. Subgenital plate in basal half largely membranous except for margins and for the erected margins of a large oval groove at very base; apical half with converging lateral margins and a shallow medial furrow; tip bilobate ( Fig. 51G ). Ovipositor elongate, substraight (very faintly curved down), with slightly converging margins; tip subobtuse ( Fig. 51I ). Measurements ( 1 female ).—body w/wings: 35; body w/o wings: 35; pronotum: 7.5; tegmen: 16; hind femur: 20; ovipositor: 23 mm .