Bioacoustics of Ornebius aurumalas

Description. Male. Typical body of genus. Head small. Rostrum swelling with furrowed distinctly, slightly wider than antennal scape; maxillary palpus with apical segment distinctly widened; third and fifth segments of equal length, a little shorter than the fourth one. Fore tibia internal tympanum large and rounded, without external tympanum. Pubescent joint of head and pronotum. Pronotum is longer than width, almost three times longer than head; posterior margin broad and convex with white scales roundly. Tegmen mostly exposed with pubescent on posterior margin ( Fig. 4A ). Hind femur 1.1 times longer than hind tibia, with sparse hairs; hind tibia 1.9 times longer than hind metatarsus with two rows of denticles about 26–28 teeth each. Cerci pubescent, different length. Abdomen: Supra-anal plate with last abdominal tergite and epiproct distinctly separated by a transverse suture and bristles along the suture; last abdominal tergite with long basolateral bristles, apex with a pair of short and roundlywide lobes, emarginate in the middle ( Fig. 4J ). Genitalia: Male phallic complex with medial valve curved to a spiral in basal part with its base forming an axis in the centre of the spiral ( Fig. 4E ). In dorsal view, two sides of the axis centre strongly projecting perpendicular of the spiral and pale yellow ( Fig. 4C ). In ventral view, internal sclerite of medial valve with two elongated and straight narrow rods ( Fig. 4D ), gently curved at the base in lateral view ( Fig. 4E ); apex widen into a transverse spade-like lobe, apical margin truncated and not surpass the apex of ejaculatory duct ( Figs 4F & G ). Ejaculatory duct basal part strongly curled into a large spiral and spermatophore sac massive. Female. Similar to male but apterous ( Fig. 4B ). There are two symmetrical irregular depressions on the surface of pronotum. Hind femur is 1.2 times longer than hind tibia. Abdomen: Supra-anal plate triangular with apex truncate, with a deep groove in middle. Ovipositor curved and smooth ( Figs 4H & I ). Colouration. Dorsal view, head and pronotum reddish-brown. Tegmen is yellowish with black posterior margin. Hind femur internal white. Abdomen brown with yellow scales on the surface. Cerci yellow. Calling song. Echeme sequence period 16–17 s, echeme sequence duration 2–4 s with 12–13 s echeme sequence interval. Each echeme sequence includes 5–10 echemes. Each echeme period 0.4– 0.45 s , echeme duration 0.05– 0.1 s with 0.35 s echeme interval. Each echeme includes 2 syllables. Echeme sequence rate is about 5 syllables/s. The dominant harmonic peak observed in the spectrogram is 5.8–6.2 kHz ( Fig. 5 ). Measurements. Male: BL 10.92, PL 3.92, PW 3.19, TL 3.35, TW 3.84, HFL 5.66, HTL 4.73, HML 1.67; Female: BL 8.34, PL 2.82, PW 2.62, HFL 5.49, HTL 3.36, HML 1.84, OL 4.63.