Byasa alcinous,[1] the Chinese windmill, is a butterfly of the family Papilionidae.

The hindwings have long tails and a chain of red spots at the edges.

The larvae feed on Aristolochia species including A. mandshhuriensis, A. debilis and A.

[3] Subspecies has been recorded on A. shimadai, A. liukiuensis, A. kankauensis, A. elegans, A. debilis, A. kaempferii, A. onoei, A. tagala, Cocculus trilobus and Metaplexis chinensis.

[2][3] This species can be found in the Asian part of the Palaearctic realm and partially in the Indomalayan realm, from Bhutan, and eastern China to the southern Ussuri region, Korea and Japan.