Diagnosis. This and the next two species, as indicated in the generic account, share distinctive features of the male forewing and genitalia. In the former, pterota has the brush basal to the blister hairlike and not extending strongly round the flap. In poiensis Prout the brush is more scale-like and extends round the margin of the flap. In murudensis Prout the brush is much smaller than in the other two species. In the genitalia, all species have a spine on the tegumen margin on each side just basal to the uncus, and the processes of the valves are also basically similar: a slender, sinuous dorsal one and a shorter, evenly curved ventral one. In pterota there is a spine at one third on the basal process directed distad. There is a similar process in murudensis, but larger and more slender, held further away from the main process which is also more slender; poiensis lacks such a lateral spine. In the aedeagus, all species have two spines at the apex of the aedeagus, the dorsal one sometimes bifid. In pterota there is a patch of coarse spines (similar to that of telisai) near the base of the vesica between the two spines. In the other two species the vesica has cornuti ventrally, both with one relatively distal, with reversed curvature, and poiensis with an additional spine near the aedeagus. There is variability in all species in the development of these spines and cornuti, so the valve characters provide the best diagnosis. The variability appears to be manifest as much within montane populations as between them. Females of pterota and poiensis are very similar, with a transverse pale antemedial and a rather irregular postmedial. In murudensis the antemedial is oblique and the postmedial is stepped, usually with a paler area between the step and the discal spot. In the genitalia the ductus is relatively short, and the processes either side of the ostium are bifid, the interior one elongate, palmate, broader in murudensis than in poiensis, where both processes are more slender and rather setose. The female of pterota has genitalia as in poiensis.
Geographical range. Peninsular Malaysia, Borneo.
Habitat preference. Bornean material consists of a series from 1200m on Bukit Monkobo in Sabah, and a male from 1600m on G. Kinabalu. In the original description, a male from about 1000m on G. Dulit and, more tentatively, a female from about 1300m on G. Penrissen in Sarawak were identified as pterota.
