Hippotion gracilis
Very similar to Hippotion eson but in general smaller, paler and with a less contrasting forewing upperside pattern. However, there is a large overlap in size and identification based on forewing pattern is not always easy in worn specimens, whence positive identification must be made by examination of the genitalia. Forewing upperside very similar to Hippotion eson but first and second postmedial lines thinner and paler, not fused (thus giving the moth an overall paler appearance); discal spot on average smaller. Male wingspan = 64.6-71.1 mm (n = 7); female wingspan = 66.9-71.1 mm (n = 4).
Male geniatlia: harpe longer and thinner than Hippotion eson; left lobe of apical process of phallus with at least four spines arranged like a cockscomb.
Female genitalia: signum shorter and narrower than in Hippotion eson with somewhat smaller teeth.