Euclea species

The Spiny Oak-Slug Moth (Euclea delphinii) apparently has a similar-looking relative, Euclea nanina [Hodges Number 4697.1], that occurs from South Carolina to Florida, and west to Texas, according to the range given at Dalton State College.

Adults of E. nanina, like E. delphinii, have a varying amount of green on the forewing (1, 2, 3, 4) and I don't know how or whether the two species can be distinguished by external appearance. Presumably the larvae are very similar also.

It's possible that some of the photos from Florida, Georgia, and Mississippi currently IDed as delphinii in the Guide are actually nanina. Does anyone have more info on this species?