Bioacoustics of Metriogryllacris (Metriogryllacris) triquetris

Figures 4–5 Description. Male. Body small with wings. Head. Face smooth. Fastigium verticis wide, approximately 2.3 times the width of the scapes, lateral margins slightly raised ( Fig. 4 ). Eyes oval; ocelli small. Apical segments of maxillary palpi longer than subapical ones, apices obliquely truncated. Thorax. Anterior margin of pronotum projecting in the middle, posterior margin nearly straight ( Fig. 4B ); lateral lobes nearly trapezoidal, longer than wide, V-shaped furrow relatively shallow ( Fig. 4C ). Fore coxae with 1 small spine. Fore and middle femora unarmed on ventral surfaces; hind femora with 11–12 internal spines and 6–8 external spines ventrally. Fore and middle tibiae with 4 pairs of spurs and 1 pair of apical spurs on ventral surfaces; middle tibiae with 1 apical spur on internal margin of dorsal surface; hind tibiae with 5 internal spines and 6 external spines dorsally, subapices ventrally with 1 pair of spurs, apices with 1 pair of dorsal spurs and 2 pairs of ventral spurs. Tegmina extends the apices of abdomen, but not reaching the apices of hind femora; hind wings slightly longer than tegmina. Abdomen. Lateral margins of the second and third abdominal tergites with two rows of stridulatory pegs ( Fig. 4D ). Eighth abdominal tergite slightly longer than seventh abdominal tergite ( Fig. 4E ); ninth abdominal tergite short, significantly curving ventrad, the middle of posterior margin with 1 pair of short processes which obviously smaller than the known species in this genus ( Fig. 4G ), not hook-shaped in lateral view, apico-ventral angle with a small spine ( Fig. 4F ). Cerci short and subconical. Basal margin of subgenital plate straight, baso-lateral margins convex and then converging, posterior margin slightly projecting with faintly concave in middle ( Fig. 4H ); styli slender and near conical, inserted on both sides of subapical area of subgenital plate ( Fig. 4H ). Female. Body slightly larger than male. Abdomen. Basal margin of seventh abdominal sternite faintly concave, lateral margins convex, posterior margin widely rounded; ventral surface of apical half concave, posterior margin of the concave narrowly separated by a furrow along the midline and the lateral margins obviously sclerotized, at tips with 1 copulatory depression on each side, the copulatory depressions nearly triangular in ventral view ( Fig. 4E ). Subgenital plate wider than long, lateral margins converging, posterior margin narrowly rounded ( Fig. 4E ). Ovipositor short, apart from subbasal curvature straight, apices obtuse; base of ventral valvulae with 2 pairs of indistinct processes ( Fig. 4F ). Coloration. Body yellowish brown, eyes black. Pronotum yellowish brown, margins light brown. Dorsal surfaces of eighth and ninth abdominal tergites black. The processes of male ninth abdominal tergite black. Measurements (mm). BL: ♂ 16.7–17.7, ♀ 21.4–22.3; PL: ♂ 3.6–4.3, ♀ 4.0–4.6; TL: ♂ 10.0–11.4, ♀ 14.6– 15.8; HFL: ♂ 9.2–9.6, ♀ 10.3–12.5; OvL: 7.3–7.8.