My first instinct was that this wasp was a cicada killer, although it didn't seem quite large enough. As I have browsed more, the best identification I can come up with is Eastern Stizus (Stizus brevipennis). Not knowing which features would "clinch" the identification, I was wondering if someone with more knowledge than I have would be able to help. The yellow-green eye color is different from the other images of this species, as are the thoracic markings. I apologize for the poor images - I was unable to get as close as I would have preferred to get even reasonable photos. The wasp was feeding on American burnweed (Erechtites hieraciifolius).