9mm. This and the next are the smallest of the Bornean species. The male antennae are not noded, and the labial palps are long, strongly recurved, but well separated from the head; the labial palps of the female are much less recurved. The wings are slightly variegated dark grey to black, the fasciae obscure except for a white band in the medial zone, that of the forewing oblique, running from the centre of the dorsum up to, and including, the discal mark, but truncated at that point. There are weak, irregular, pale submarginals on each wing, following a similar course to those of pallifascia. The male genitalia are typical of the genus, similar to those of mysalis, though with a straighter uncus and narrower valves. The apex of the aedeagus has a series of fine, rugose ridges. H. purifascia Prout (Sumatra) has very similar facies but is larger, with a wing span of 24mm rather than, at most, 19mm, and the male antenna is thickened by a tuft of scales at about two-fifths.
Paratype. INDONESIA: Borneo, Kalimantan Tengah, Barito Ulu 2001, at Busang / Rekut River Junction, 0°38' S, 113°59' E, viii.2001 (G. Martin), BM noctuid slide 20070.
Taxonomic note. The epithet angustifascia validates a manuscript name of A.E. Prout applied to Javan material.
