This photo taken by my friend Leicneagra Leic at Curup town in Rejang Land, South West Sumatra, Indonesia on october 2009.
Diagnosis. The male is dark, rather purplish brown with slender, strongly falcate forewings. The zone distal to the submarginal is distinctly paler on the forewing. The female has prominent double white submarginals on a dark brown ground, that of the forewing broadening into a triangle at the apex, that of the hindwing looping round the ocellus anteriorly.
Taxonomic notes. The name youngi as used here applies to all Sundanian populations of assamensis, distinguished by a darker, less rufous brown ground colour. The taxon gschwandneri Niepelt, mentioned by Allen (1981), is referable to A. celebensis Watson rather than assamensis.
Geographical range. India, Burma, Sundaland (Sumatra and peninsular malaya).
Habitat preference. The species has been taken infrequently in lowland forests.
Biology. Arora & Gupta (1979) recorded the following host-plants for Indian assamensis: Cinnamomum, Laurus, Litsea, Persea (Lauraceae); Magnolia, Michelia (Magnoliaceae); Quercus (Fagaceae); Sarcostemma (Asclepiadaceae); Symplocos (Symplocaceae).