Identification based on other images in the guide--this is apparently the only widespread shieldback genus in the east. This individual was found hopping around in the leaf litter on the high, dry, part of this site.

Given the early date, this is probably a nymph. Seems that the wings don't poke out beneath the pronotum at all. This individual looks rather like this photo of an (adult) male American Shieldback, A. americana at Singing Insects of North America. This is a tough group.