, 13-14mm. This is the smallest of the Bornean species with the Bomolocha type of facies, resembling most closely rhombalis Guenée (India, China, Japan) and the next species in the way the forewing brownish black area is separated from the dorsum by a pale whitish wedge that runs from the base to the pale postmedial that then extends to the costa, at first angled obtusely at one third, then acutely in the discal area, the final section to the costa being concave distad. The acute angle is not produced and suffused into the apical black zone so completely as it is in rhombalis, and the curvature of the inner margin of the pale wedge into the postmedial is not so even, partly because of the obtuse angle in the latter. The shape of the black area is very similar to that of the European H. crassalis Fabricius, but the area outside this is different in that the submarginal is less conspicuous, its white lunules, where present, being more shallowly curved. The apical lens is more sharply defined in crassalis where it is diffuse in apiensis, and also narrower. The male genitalia have a short, rather open pleat in the centre of the valve base, though with an obtuse angle in its ventral edge that extends distally to a small semicircular protrusion. The female genitalia are distinct from those of telamonalis, the females of which apiensis also resembles somewhat in facies, having a shorter, curved ductus with a much broadened ostium, and a narrow corpus bursae that tapers gently basad and has no areas of scobination. In telamonalis the ductus and bursa together are almost twice as long, the ostium narrower and more elongate, ventrally cleft with a pair of rather rugose projections flanking the apex of the cleft. The basal part of the ductus bursae is also slightly tapered but twisted as well. The part distal to the twist is inverted with narrow, small, hair-like spines, grading into a patch of much coarser spines just subapically. In crassalis the corpus bursae is similarly immaculate, but of more even width, expanding abruptly from the base rather than gently. The ductus bursae is longer but narrower and is not curved, and the expanded basal part is also longer but slightly narrower. See also the next species.
Holotype. SARAWAK: Gunong Mulu Nat. Park, R.G.S. Exped. 1977-8 (J.D. Holloway et al.), Site 25, April, G. Api, 900m. 427550, lower montane forest, BM noctuid slide 19597.
Paratypes: 4, 1 (slide 19930) as holotype; 1 as holotype but Site 26, April, G. Api, Pinnacles, 1200m, 428545, open scrub.
Geographical range. Borneo.
Habitat preference. All material is from lower montane forest on limestone.
13-14mm. This is the smallest of the Bornean species with the Bomolocha type of facies, resembling most closely rhombalis Guenée (India, China, Japan) and the next species in the way the forewing brownish black area is separated from the dorsum by a pale whitish wedge that runs from the base to the pale postmedial that then extends to the costa, at first angled obtusely at one third, then acutely in the discal area, the final section to the costa being concave distad. The acute angle is not produced and suffused into the apical black zone so completely as it is in rhombalis, and the curvature of the inner margin of the pale wedge into the postmedial is not so even, partly because of the obtuse angle in the latter. The shape of the black area is very similar to that of the European H. crassalis Fabricius, but the area outside this is different in that the submarginal is less conspicuous, its white lunules, where present, being more shallowly curved. The apical lens is more sharply defined in crassalis where it is diffuse in apiensis, and also narrower. The male genitalia have a short, rather open pleat in the centre of the valve base, though with an obtuse angle in its ventral edge that extends distally to a small semicircular protrusion. The female genitalia are distinct from those of telamonalis, the females of which apiensis also resembles somewhat in facies, having a shorter, curved ductus with a much broadened ostium, and a narrow corpus bursae that tapers gently basad and has no areas of scobination. In telamonalis the ductus and bursa together are almost twice as long, the ostium narrower and more elongate, ventrally cleft with a pair of rather rugose projections flanking the apex of the cleft. The basal part of the ductus bursae is also slightly tapered but twisted as well. The part distal to the twist is inverted with narrow, small, hair-like spines, grading into a patch of much coarser spines just subapically. In crassalis the corpus bursae is similarly immaculate, but of more even width, expanding abruptly from the base rather than gently. The ductus bursae is longer but narrower and is not curved, and the expanded basal part is also longer but slightly narrower. See also the next species.