Phalera styx

Appearance

25-27 mm. The forewings are very dark blackish grey with a slightly paler subapical patch as illustrated; curved double postmedial and darker subbasal fasciae are faintly visible as are several fine, acutely zig-zig lines medially. The hindwings are almost black. The species forms a related trio with P. melantata West comb. rev. from Luzon and P. erconvalda Schaus comb. n. from Mindanao. In the Philippines species the forewings are apically much more acute, the margins less rounded, and the markings, especially the pale subapical patch, more obscure. In the male genitalia of styx the uncus is twice as deep as in melantata, the gnathal processes massive, mandibulate, rather than more slender, planar, bifid; the valves are longer, triangular rather than oval, with the subapical processes more developed. In erconvalda the gnathal processes are similar to those of melantata but the valve is half as deep again and the uncus twice as deep.

Distribution

Borneo

Habitat

The majority of specimens have been taken in rich lowland dipterocarp forest, and were especially abundant in a sample made during the Mulu survey; on the bank of a river terrace rising up from alluvial forest to kerangas near the Melinau Gorge.