Identification of a caterpillar from NY
Based on this picture, I'd say it's a Macrurocampa marthesia. I realize your specimen lacks the split tail, but I note that the "tails" of the larva of this species are longer in earlier instars. I wonder if this one is just an older caterpillar, getting ready to pupate? The image is a very good match otherwise, and this species does occur in the appropriate range.