Bioacoustics of Typophyllum mortuifolium

Description. The only remaining member of fourth group according to Vignon (1925a) , characterized by radial vein of tegmina slightly curving downward from base to tip (or forward when spread). In both sexes the tegmina have a shallow distal emargination at the lower margin. Females often bear a ring of transparent patches in the costal area ( Fig. 18 ). In the smaller males the dorsal (anal) margin is much more curved than in females (photos in OSF). The speculum is translucent. In the only female specimen found as adult in the investigation area, the large distal spine of the fore femur is lobiform and almost perpendicular ( Fig. 17 A,C), which seems to be an abnormal state. Usually it is more spiniform and directed ventrally like the other spines. The prosternum is spineless, meso- and metasterum bear small spines. Coloration. Light green, legs sometimes light brown, tegminal margin at distal emargination as well as margin of transparent windows in tegmina brownish. Measurements. Tegmen length in males 20–25 mm and in females 34–39 mm , hind femora in males 14–16 mm and in females 19–26 mm . Acoustic behaviour. Producing squeaky chirps in the audio range, which can be repeated over several minutes without pause ( Morris et al. 1989 ). Individual chirps consist of two sustained sinusoidal pulses, and the spectrum shows a very narrow peak at 9.4 kHz (op. cit.). Mating behaviour. Also performing precopulatory riding of the smaller male on the female, sitting sidewise on one tegmen, as in the other species ( Nickle & Castner 1995c, photo by R. Oelman ).