Callambulyx junonia can be distinguished from the other members of the genus by the presence of a complete eyespot on the hindwing upperside. Uncus in form of an inverted fish tail with apex excavated so forming a forked structure, sides concave and base about as broad as apex. Valva narrow apically; harpe with a pointed hook distally and several teeth more proximally.
Despite its wide range, DNA barcodes of samples of Callambulyx junonia from Shaanxi, Gansu, Sichuan, Yunnan and Vietnam all form a tight cluster within a single BIN (AAC5032). The sole specimen known from Thailand was collected at Lom Sak (Lindt & Viidalepp, 2007). There is a specimen of Callambulyx junonia in CMNH labelled simply "N.W. India". As this record cannot be localized to a particular state, it is not mapped.