Ambulyx elwesi Druce, 1882, Entomologist's mon. Mag. 19: 17. Type locality: [India, West Bengal,] Darjiling [Darling].
Synonym. Ambulyx elwesi Druce, 1882.
Wingspan: 100mm. Superficially similar to a very dark Callambulyx rubricosa rubricosa but differing markedly in genital and other morphology. Frenulum present but reduced in length; retinaculum absent. Subapical pair of hindtibial spurs absent. Forewing upperside with distal two-thirds dark and proximal one-third green (turning brown in a humid atmosphere) and much paler. Hindwing upperside with deep pink basal area and a dark, almost black distal two-thirds in which a narrow lunate purple patch is discernible.
In Nepal at 2000-2500m altitude in oak-laurel forest (M. C. Allen, pers. obs. 1991).
In Thailand, May to July at 700-1000m altitude. Mid June in Nepal (M. C. Allen, pers. obs. 1991).
Larval hostplants. Unknown in the wild, but reared in captivity on Salix (Tomáš Melichar, pers. comm. 2017). Therefore, probably feeds on a tropical member of the Salicaceae.
Northern Pakistan (Rafi et al., 2014), northern India, Nepal, Bhutan (Irungbam & Irungbam, 2019), southwestern China, Burma/Myanmar, northern Thailand, northern Laos and northern Vietnam.