Truxalis viridifasciata (Krauss, 1902)

Figs 19, 20

References for Socotra.

Burr 1898: 384 [as Tryxalis nasuta]; Krauss 1902: 4 [as Acrida (Acridella) viridifasciata]; Burr 1903: 412, 416 [as Truxalis nasuta]; Krauss 1907: 18, 29, plate II: figs 1, 1 A [as Acrida viridifasciata]; Dirsh 1950: 196–199, figs 125, 126; Popov (in Uvarov and Popov (1957)): 383, figs 37, 38; Wranik 1998: 158, 171; Wranik 2003: 325, plates 153, 158.

Diagnostic notes.

Truxalis viridifasciata can be distinguished from Oxytruxalis ensis by the following characteristics: antennae shorter than head and pronotum combined; pronotum saddle-shaped; tegmina more abruptly narrowed and obtusely pointed apically; hind wings only somewhat shorter than the tegmina; both the upper lateral lobes (inner and outer) of the hind knees of more or less the same length. Only adults of Oxytruxalis and Truxalis can be separated, based on the above characteristics. Nymphs are much harder to identify since their wings and the shape of the pronotum have not yet fully developed.

We identified the nymph specimens in our collection and those collected by Wranik as T. viridifasciata, based on the equal length of the inner and outer dorsal spurs on the hind knees. A nymph mentioned by Burr (1898) under Truxalis nasuta (Linnaeus, 1758) is also considered to belong to this species (Krauss 1907; Popov in Uvarov and Popov 1957).

Distribution and occurrence.

The species is endemic to Socotra. It is relatively widespread in the Hagher, the surrounding limestone plateaus and the lower plains, but is uncommon (Fig. 20).

Habitat and biology.

The species occurs in various habitats between 35 and 1000 m a. s. l. Most records are from sparse dwarf, Croton - Jatropha - and submontane shrubland, submontane grassland and open woodland. Both adults and nymphs are present in all seasons.

Bioacoustics.

This species supposedly produces a song. Members of Truxalini are known to possess a stridulatory apparatus and can produce sounds through crepitation by snapping their hindwings during flight (Harz 1975; Haggag and Badawy 2017).