Ochrilidia gracilis subsp. nyuki

Ochrilidia gracilis nyuki (Sjösted, 1909) Figs 47, 48 References for Socotra. Jago 1977: 191, figs 74, 76, 79, 100; Guichard 1992: 186. Diagnostic notes. The main diagnostic character of Ochrilidia gracilis nyuki is its fastigium of the vertex that protrudes extensively in front of the eyes. The part of the fastigium in front of the eyes is much longer than the maximum width of the vertex at the frontal edge of the eyes in dorsal view. In the nominate ssp. (not present on Socotra), the fastigium in front of the frontal edge of the eyes is as long as it is wide (Jago 1977). The antenna segments 2–8 are very wide and flattened compared to the other segments, much more so than in the two other occurring species. The temporal foveolae are invisible from above (Fig. 47) (Jago 1977). The inner ventral lobes of the hind knees do not bear a black dot. Distribution and occurrence. O. gracilis occurs in North Africa and the Middle East, eastwards through Iran and into India. The ssp. nyuki is confined to the Horn of Africa and Socotra. Its occurrence on Socotra is only known from one collecting event at Hadiboh Plain in 1967. Habitat and biology. According to Guichard’s travel journal, O. gracilis has been found in a “ new tufted grass habitat near the foot of Ras Hazira M …. [= Moukaradia Pass], north [not north, but west] of Hadiboh ”. Jago (1977) described the habitat of O. gracilis as riverine floodplains and well-watered areas by run-offs from massifs and plateaus. Adaptation to these wet habitats in north-eastern Africa and Socotra has led to the evolution of the elongated ssp. nyuki according to Jago (1977). Bioacoustics. The song of this species is unknown.