Identification of a caterpillar from NY I recently camped at Harriman State Park in Southern New York, in early October. Upon returning home, I noticed that I had a passenger with me. The caterpillar in question is an almost translucent, pale green color with a single reddish stripe running down the center of the back. It is approximately 1.5 inches long, with a reddish face as well. I tried using a caterpillar identification book, but the closest one I could find also had a split tail, which this one does not. ](

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.