The goldenrod (Solidago sp.) and boneset (Eupatorium sp.) flowers at Scherman Hoffman were pretty to look at but were full of lurking predators. Some of them were various types of spiders, but the most numerous seemed to be these green and brown bugs. These unusual-looking insects are ambush bugs (subfamily Phymatinae, probably genus Phymata).
Ambush bugs sit still on flowers and stems and wait. When an unsuspecting insect approaches to sip a flower's nectar, it grabs the insect with its hooked forelegs and eats it.