, 16mm. The forewing facies is reminiscent of that of rhombalis Guenée (India to China and Japan; also Java) and luzonensis Wileman & West (Philippines), but the genitalia indicate a closer relationship to apiensis. In the first two species the posterior margin of the forewing black area has a smooth curvature, particularly in luzonensis where the gap between it and the dorsum is wider centrally at the point where the curvature is stronger in rhombalis. In rhombaloides this curvature is slightly angled at this point and again more distally opposite the tornus. The projection at one third from the costa is more extreme than in apiensis, resembling that of luzonensis. The costal subapical lens is shorter than in rhombalis or luzonensis, with its basal edge meeting the costa in the perpendicular rather than obliquely, but with a much stronger curvature than that of apiensis. The parts exterior to the black area are paler and more contrasted in the female. The male genitalia resemble those of apiensis, sharing the features of the valve pleat and the rather slender, elongate aedeagus where the flexure is central (also in rhombalis) rather than more distal (luzonensis) and where the vesica lacks any prominent spine clusters (seen in both rhombalis and luzonensis). The female genitalia are similar to those of apiensis but the ductus is not quite as short or strongly curved, and the corpus bursae is relatively longer.
Holotype. N. BORNEO: Kidukarok, 3.ix.56, Cambridge N. Borneo Exp., BM noctuid slide 19967.
Paratype. SARAWAK: Gunong Mulu Nat. Park, R.G.S. Exped. 1977-8 (J.D. Holloway et al.), Site 2, January, Camp 4, Mulu, 1790m. 452463 [upper] montane (moss) forest, BM noctuid slide 19932.
Taxonomic note. A similar species occurs in Sumatra (slide 19969; see also the record of rhombalis for Sumatra by Lödl (1999e)). The text above provides evidence that H. luzonensis Wileman & West stat. rev. is distinct from rhombalis rather than a synonym as indicated by Lödl (1999e).
Geographical range. Borneo.
Habitat preference. The species is montane. Kidukarok in Sabah has not been located; kidukarok is a Kadazan word for an edible yam (Chey Vun Khen, pers. comm.).
16mm. The forewing facies is reminiscent of that of rhombalis Guenée (India to China and Japan; also Java) and luzonensis Wileman & West (Philippines), but the genitalia indicate a closer relationship to apiensis. In the first two species the posterior margin of the forewing black area has a smooth curvature, particularly in luzonensis where the gap between it and the dorsum is wider centrally at the point where the curvature is stronger in rhombalis. In rhombaloides this curvature is slightly angled at this point and again more distally opposite the tornus. The projection at one third from the costa is more extreme than in apiensis, resembling that of luzonensis. The costal subapical lens is shorter than in rhombalis or luzonensis, with its basal edge meeting the costa in the perpendicular rather than obliquely, but with a much stronger curvature than that of apiensis. The parts exterior to the black area are paler and more contrasted in the female. The male genitalia resemble those of apiensis, sharing the features of the valve pleat and the rather slender, elongate aedeagus where the flexure is central (also in rhombalis) rather than more distal (luzonensis) and where the vesica lacks any prominent spine clusters (seen in both rhombalis and luzonensis). The female genitalia are similar to those of apiensis but the ductus is not quite as short or strongly curved, and the corpus bursae is relatively longer.