Charaxes solon, the black rajah, is a butterfly species found in tropical Asia. It belongs to the Charaxinae (rajahs and nawabs) in the brush-footed butterfly family (Nymphalidae).
The black rajah is a medium-sized butterfly with a 70- to 80-mm wingspan. Above, the butterfly is dark brownish black with greenish or white discal bands across both the wings. The band is broken into spots towards the apex of the fore wing. The hind wing has two similar-sized tails at veins 2 and 4. These tails are longer in the females and more pointed in the males.
Its egg is transparent yellow and spherical, with longitudinal ridges. It has a dark red, uneven band around its upper half.
The caterpillar is dark green with irregular rows of yellow tubercles. The caterpillar is cylindrical and may have a round white blotch on the seventh segment. The head is curved out and has horns and spines. The pupa is short and dark green, with a lateral longitudinal line marbled with white.
The butterfly is found in South and Southeast Asia. It occurs in Sri Lanka, India, Myanmar, Indochina, Cambodia, Peninsular Malaysia, Singapore, Sumatra, Sulawesi, and the Philippines (Palawan, Sulu Archipelago). In India, the butterfly occurs in South India, and the Himalayas from Kumaon, Sikkim, into Bhutan, through Assam, and onto Myanmar. At least in South Asia, it is not rare.
