Type(s) "India orientali" [coll. O. Thott, ?ZMUC]. Although Zimsen, 1964, Type material I.C. Fabricius: 519, considered the type(s) to be lost, there is a male labelled "type" in the Kiel coll., ZMUC.
Transferred to Nephele by Butler, 1876, Trans. zool. Soc. Lond. 9: 624, who fixed Sphinx hespera as the senior name under the Principle of the First Reviser. Reinstated as the correct name for the species by Kitching & Spitzer, 1995, Tinea 14: 185. Implicitly resynonymized with Nephele didyma by Zhu & Wang, 1997, Fauna Sinica Insecta 11: 308. Implicitly reinstated as the senior name by Kitching & Cadiou, 2000, Hawkmoths of the world: 60.
The name “hespera” also applies to the form in which the forewing upperside lacks silver spots, or has only a single, minute spot.