Diagnosis. This species is similar in size to melinau but more distinctly marked. The forewing discal mark is a dull yellow figure eight, the posterior circle larger and centred with a more conspicuous black dot than the anterior one. The postmedial fascia distal to this and its counterpart on the hindwing are finely darker, irregular and distinct, with a similar, but paler submarginal fascia distal to each. There is a fine dark medial fascia on the hindwing but that of the forewing is obscure. The antennae and labial palps are as in melinau. The holotype (Plate 9) is somewhat faded and worn. The male genitalia have a slightly sinuous, apically down curved and acute uncus. The valve is narrow, apically spatulate beyond a central constriction which is marked by a large, distally directed spine from the costal margin. The aedeagus vesica has a robust cornutus but this is shorter than in melinau and simple.
Taxonomic note. The species was listed as a synonym of ineffectalis by Poole (1989) as noted above, and is closely related to the generic type species, N. bisignata Walker stat. rev. (OUMNH slide 433-964; female), that was also so listed, having generally similar facies and male genitalia. Both taxa are distinct and are part of a complex that extends through the Philippines (slides 3845 (female), 20046 (male)) and Sulawesi (slide 20082) to Seram (slide 20085). The females lack the broadly bilobed structure at the ostium and have a large corpus bursae associated with an appendix bursae half the size. The corpus bursae is finely but sparsely spined over the distal two thirds. The male genitalia have valves with a paddle-like or digitate cucullus and a process just basal to the narrowing at the base of the cucullus. In laufellalis, this process is an appressed spine and the cucullus is paddle-like; in the Philippines male the spine is more thorn-like; in the Sulawesi male it is vestigial, and the cucullus is more digitate; in the Seram male it is absent, and the cucullus is as in the Sulawesi male. All the species have a long cornutus in the aedeagus vesica. This is: tapering, less than halfa the length of the aedeagus in laufellalis; almost as long as the aedeagus and very slender in the Philippines male; a similar length but more robust and apically curved in the Sulawesi male; more robust, slightly wavy and a similar length in the Seram male. It is likely, therefore, that the Seram and Sulawesi males are referable to bisignata and that the Philippines material is of a distinct species, more closely related to laufellalis. There is a further, somewhat larger species in Sulawesi (slide 20083) with a more elongate valve extending well beyond the base of the uncus rather than just to it, with a broad but blunt process at the base of the cucullus, and with a cornutus in the vesica larger and more robust than that in laufellalis.
Geographical range. Borneo.
Habitat preference. The holotype was taken in Sarawak by A.R. Wallace, probably in the lowlands. The only other specimen is from Kuching, the coastal capital of Sarawak.
