This is a Rapids Clubtail, a somewhat uncommon and localized species. It is one of our smaller clubtails.
All of my Rapids Clubtail sightings have been in late May to mid-June (between May 25 - June 18). This species has a mass, synchronized emergence. You need to be in the right place at the right time to see them.
I usually see Rapids Clubtails at Germantown MetroPark, but I also have one sighting along the Great Miami River at Miamisburg.
The top of the club (Segments 8 and 9) is all black in this Rapids Clubtail. A Lancet or Ashy Clubtail would have yellow on the top of these segments.
Another distinctive feature is that a Rapids Clubtail has two yellow half-circles on the sides of the club.
The eye color changes with age. This young Rapids Clubtail has pale gray eyes; some of the more mature individuals on this page have dark green eyes.