Mating blue dashers. That's the female turning her abdomen in towards the center of the more colorful male.
Once, uh, mated, the female dips her abdomen down to lay eggs.
Eastern amberwing, our smallest dragonfly, showing amber shadows. We also saw a huge darner dragonfly of some sort, not a green darner, easily three inches long, in the cemetery, later overhead in Cobble Hill, and then even later in the evening at the band shell at Prospect Park.