Rudbeckia is just starting to flower in open, sunny, dry locales. The bright yellow rays make excellent platforms for visiting insects. Some visitors are not only waiting for the central disk to develop its florets providing nectar and pollen, but for the bees it will attract.
Several of these Blister Beetles (Nemognatha species) were aggregated on the flowers this week.
They have strange looking mouthparts consisting of long maxillae that they use to suck nectar.
There's another reason why they visit flowers although, "females lay eggs on flowers, larvae attach to visiting bees and are carried to visiting bee nests where they eat bee eggs and stored food." (BugGuide.net)
Some of the first Jagged Ambush Bugs (Phymata pennsylvanica) of the season are on the Rudbeckia flowers. With their sickle-like enlarged forelegs, they wait for an unsuspecting insect to land on the flowers and 'ambush' them.