Bioacoustics of Xenogryllus ululiu

Redescription. In addition to the characters of the genus, X. ululiu has an average size and a light brown or golden brown coloration ( Fig. 2 I–L). Head ( Fig. 3 M–N): Fastigium slightly widened apically, as in X. transversus and X. maichauensis ( Fig. 4G ); eyes rather small, restricted to the dorsal third of head in lateral view ( Fig. 3N ). Pronotum dorsal disc with a wide median black longitudinal band, its lateral angles not carinated, with a thin yellow band underlined by a black line ventrally. Hind wings tail gray brown, near twice as long a pronotum. Male. FW venation ( Fig. 5H ): 1A forming a straight angle. Dark coloration anterior to 1A not including angle of file. Harp wide, with one short incomplete oblique vein and two complete ones slightly bisinuate. Mirror large, slightly wider than long, less rounded than in X. maichauensis and X. transversus , its inner margin curved as in these species. Apical field forming a triangle longer than wide, with 6–7 (n = 5) cell alignments. Male genitalia ( Fig. 7 Q–R): Pseudepiphallic lophi stocky, basally fused together, with a sharp apex and a strong dorsal preapical expansion ( Fig. 8H ). Rami strong, convergent apically. Ectophallic apodemes strong, lamellate apically. Ectophallic fold and endophallic sclerite almost fused, forming a long ventral gutter, trifurcate posteriorly and extended anteriorly between rami. Endophallic apodemes made of anterior lateral lamellas. Female. Head larger than in male ( Fig. 2 K–L), wider than rest of body in dorsal view. Dorsal disc of pronotum almost rectangular, its posterior margin slightly bisinuate. FWs light brown, anterior dark spot small. Dorsal field with nine strong longitudinal veins. Subgenital plate with a wide, apical U-shaped indentation with sharp edges ( Fig. 9E ). Ovipositor as long as FIII. Female genitalia: Copulatory papilla small, conical, its apex rounded and sclerotized ( Fig. 11 K–L). Life history traits. According to S. Ingrish who recorded the species’ call in Thailand , males of X. ululiu sing at night in grassy undergrowth of mixed Oak-Pine forest or bamboo thicket ( Cigliano et al. 2018 ). Calling song ( Figs 12E , 18 ). One male from Thailand was recorded by S. Ingrish at 21°C. The song consists of echemes during 566 ± 57 ms, with a period of 2041 ± 358 ms. Echemes are made of 4 or 5 syllables (m=5), with syllable duration = 108 ± 3.8 ms and syllable period = 120.3 ± 3 ms. Within echemes, the three starting syllables have a lower amplitude than the final 1–2 syllables. Dominant frequency is 4.8 ± 0.4 kHz and corresponds to the fundamental frequency of the spectrum. Measurements. See Table 9 .