Papilio chaon (??)

Chaing Mai Thailand recto ssp ducenarius Chaing Mai Thailand verso ssp ducenarius
Assam, N. India; 7/71 ssp chaon

   NE India through S China, Probably only a subspecies of P. nephelus. Common. Ssp rileyi (Hainan and S China) would belong to chaon if it is treated as a full species, otherwise both chaon and rileyi belong to nephelus. The specimens from the Malay peninsula are generally closer to nephelus, though ducenarius (Thailand) and annulus (N Malaysia) seem closer to chaon and I suspect would also belong to it.