Cupha erymanthis, the rustic, is a species of brush-footed butterfly found in forested areas of tropical South Asia and Southeast Asia. The males and females are identical.
The rustic caterpillars feed mainly on Flacourtiaceae species, for example Flacourtia montana, F. ramontchii, F. rukam, Xylosma racemosa and Scolopia species. They also eat plants such as Glochidion eriocarpum and Lepisanthes rubiginosum.
Adult butterflies occasionally visit carrion to drink the fluids. They seem to favour carcasses lying in exposed, sunny areas over those which are in the shade.