Amphion floridensis, the Nessus sphinx, is a day-flying moth of the family Sphingidae.

It is the only member of the genus Amphion erected by Jacob Hübner in 1819.

It lives throughout the eastern United States and Canada and occasionally south into Mexico, and is one of the more commonly encountered day-flying moths in the region, easily recognized by the two bright-yellow bands across the abdomen.

[3] The adults feed on the nectar of various flowers, including Syringa vulgaris, Geranium robertianum, Kolkwitzia amabilis, Philadelphus coronarius, and Phlox species.

This name was invalid, because Dru Drury had already used it for another species (Theretra nessus) in 1773.