Delias

Delias is a genus of butterflies. There are about 250 species of the genus Delias, found in South Asia and Australia.They are remarkable for the gay-coloured under surfaces of very many species which often show an altogether ideally beautiful arrangement of intensively coloured bands and spots, more gorgeous than are found either in America or in Africa. The Delias are a characteristic feature of the IndoAustralian fauna. They enliven the woods and their borders, as Appias and Catopsilia predominate at the river-banks, fly often round the tops of the forest-trees, are fond of resting on leaves and flowers (for instance on those of the Cinchona-tree, the Lantana) or in rarer cases speed over grassy plains in wild, irregular flight (battana in South Celebes). But most species fly slowly and quietly from flower to flower and often do not even leave the bush on which, frequently to the number of many hundreds, they emerged from the pupa (belisama on Java). Comparatively few species are distributed over large tracts of country, most remain local or insular; they are inclined to geographical variation, even on the same island (bromo, fruhstorferi in East Java and crithoe, momiea in West Java, which are so different that they were described as separate species). But they are by no means particular as to their place of flight and we meet with them at the seashore in mangrove thickets (from whence they often fly out even over the sea), on the high volcanoes of the Malayan Archipelago and in the Himalayas, where they are common up to 8000 ft., but also ascend to 10 and even 11,000 ft. The eggs are laid on the underside of leaves, often 20—-30 in parallel rows. Larva cylindrical with two rows of long hairs, lives on mistletoe (Loranthus longiflorus); but one species (eucharis) was also observed on Hibiscus chinensis. Pupal stage usually lasts 10 days, pupa fastened at the end of the tail, with the head upwards, often very abundant on tree-trunks, branches and even walls.

The genus is considered to have its evolutionary origins in the Australian region.