15mm. This and the next species differ from larusalis in being slightly larger, with the forewing postmedial gently sinuous rather than straight. Basally within the pale costal zone of the forewing is a dark brown ovate mark, separated by the pale colour from a smaller, more triangular mark distad. In muluensis the hindwings are shaded much darker than in larusalis males and those of the next species, though not as much as in larusalis females. The male genitalia have the spur at the apex of the costa of the valve more subapical than in larusalis or the next species, and intermediate in size between the two. The aedeagus vesica has coarse spines separated as in the next species, but in a distinct band; the distal diverticulum is central, rather than ventral as in the other two species, and bifurcates into a broad process with fine scobination and a narrower, tapering one with slightly coarser spining.
Holotype. SARAWAK: Gunong Mulu Nat. Park, R.G.S. Exped. 1977-8 (J.D. Holloway et al.), Site 3, January, Camp 4, Mulu, 1780m, 453463, [upper] montane forest, BM noctuid slide 19500.
Geographical range. Borneo.
Habitat preference. The only specimen is from upper montane forest.
