This is a Lancet Clubtail. My personal nickname for Lancet Clubtails is "Lilliputian Clubtail" because they are so small compared to most of the other clubtails I see. Lancet Clubtails get their name from a downward-projecting blade on the cerci, which distinguishes this species from the Ashy Clubtail in close-up photos. 

Ashy Clubtail, photographed at Germantown MetroPark. This species has a lot of variation, depending on the geographic region. In other parts of North America, Ashy Clubtails have much duller colors and little or no yellow on the top of the club (Segment 9). However, most of the Ashy Clubtails in our area are fairly brightly-colored. 

Ashy Clubtails have an early flight period. They can be found from mid-May through mid-June. They are fairly widespread. There is a good population at Germantown MetroPark. I have also seen Ashy Clubtails at a few of the Beaver Creek Wetlands parks (including Siebenthaler Fen), Spring Lakes Park in Bellbrook, Clifton Reserve, Pointe North in Urbana, and a few locations along the Little Miami River.  

This is another Lancet Clubtail. I have found Lancet Clubtails at Pointe North in Urbana, Germantown MetroPark, Clifton Gorge, and the Beavercreek Wildlife Area. They typically fly in late May and early June, although I have one late sighting on July 11th. The fight period runs a little later for Lancets than Ashies. You are more likely to see Lancets at ponds and Ashies at streams, but there are exceptions in both cases. Many field guides say that Lancets are more common than Ashies, but my experience has been exactly the opposite. I see far more Ashies than Lancets. 

Ashy Clubtail cerci

Lancet Clubtail cerci

This is another Ashy Clubtail. Ashies can be difficult to distinguish from the similar Lancet Clubtails. In the field, Lancets are noticeably smaller. Ashies are longer and thinner; Lancets are short and chunky. The club on an male Ashy Clubtail is thin and narrow; it is a bit wider in a Lancet. Lancets often have a long yellow streak on the top of Segment 8, while Ashies usually have a shorter streak or yellow triangle. Also, adult Ashy Clubtails often have violet-gray eyes rather than the blue-green eyes of a Lancet Clubtail. (But some mature Ashies do have blue-green eyes, so don't rely on this feature alone.) The best way to distinguish these two species is with a close-up photo of the cerci.  

This Ashy Clubtail is not as brightly marked as most of the individuals I see. It only has a thin, faint line of yellow on the top of Segment 9. In other parts of the country, Ashy Clubtails tend to have duller colors like this. 

Teneral Ashy Clubtail at Germantown MetroPark.