Adhemarius eurysthenes is a species of moth in the family Sphingidae. It was described by R. Felder in 1874, and is known from Brazil, Colombia and Paraguay. It is similar to Adhemarius palmeri, but the forewing upperside subbasal band is complete and irregular along proximal margin, the antemedian oblique line is very narrow, almost transverse and reaching the costa just distal to the subbasal band and the subapical patch is smaller and bluntly triangular. The hindwing upperside marginal band is also narrower.