The difficulty of defining species in this genus is increased by the constancy of the local form or races. I have elsewhere referred (Ent. News, VII., 218) to the race of fulvicosta which Mr. O. D. Foulks has discovered at Stockton, Md. Mr. Foulks was so kind as to send me over 100 hibernated larvæ, from which I bred a long series of moths. The type form is large, the size of reversa and colona, both wings immaculate yellowish-white, head, collar and the tips of the abdominal rings ochre-yellow.

In var. A the fore wings are nearly pure white, the hind wings much yellower, suggesting conscita, though never so dark as that form.