This genus is very close to the Polypogon complex, though excluded by Poole (1981). The Japanese species were reviewed by Owada (1987, 1992). The male foretarsus is reduced to a single acute segment within the tibial sheath as in Herminia as recognised by Owada, but the facies is atypical of the complex in having irregular transverse fasciation, including the obtusely angled hindwing submarginal where the angle is weak in most of the typical brown group of species but barely evident in the subgroup with the Bornean species. Owada (1987) distinguished the genus from Herminia by the strongly sclerotised valve in the male and small, slender, weakly sclerotised ovipositor lobes in the female. The male valves are much more diverse in form than in Herminia, lacking its characteristic costal process (p. 124).
One subgroup of the genus has distinctive facies and ranges from Japan to New Guinea, with two species in Borneo. Its relationship to the typical group is unclear. The male antennae vary from ciliate through fasciculate to bipectinate. The general colour of the wings is a pale pinkish grey. The forewing is traversed by three dull pale orange fasciae that are edged black on each side, though this may fluctuate in extent. The medial fascia is broader than the antemedial and postmedial ones and encloses the strongly lunulate white reniform stigma, also edged with black. There is an irregular, broken black submarginal, usually present only subapically and subtornally, where the black flecks are edged white distad. This is also represented on the hindwing, usually just as an angle near the tornus; there are similar but fainter postmedial and medial fasciae basal to it.
The male abdomen in the Bornean species has a very weak framed corematous structure on the sternite, but the tergite has well separated, rather triangular apodemes. The genitalia have the uncus variously modified, often with a dorsal peak, angle or spine subbasally, rather as in Hipoepa (see below). The valves are variable, being narrow in albeola Rothschild, with a subapical spur on the costa as in typical Isana species (p. 54), but robust and more extensively ornamented in the new Bornean species. The aedeagus vesica is usually scobinate but can have more robust cornuti basally or spining on the apex of the aedeagus itself.
The female genitalia are typical of the Polypogon generic complex, with a horseshoe of spines in the corpus bursae.
The species included in this subgroup are S. lunifera Moore (Sri Lanka), S. discisigna Moore (N. India, Nepal, Thailand (Kononenko & Pinratana, 2005)) S. c-album Owada (Japan) and the two Bornean ones below.
The typical group includes three species with larvae that feed on moss (Owada (1987) and in Sugi (1987: 239-244) and references therein).
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