Male Skimming Bluet, photographed at Spring Lakes Park in Bellbrook. Notice that only two segments near the tip of its abdomen are blue (as opposed to three in Azure Bluets). I see most of my Skimming Bluets in May and June. However, I found several late individuals in October 2017 due to unusually warm autumn weather. (My personal late sighting is October 22, 2017.)  

Female Azure Bluet. Notice that the spots between the eyes are pale green rather than blue, and the last blue spot on the abdomen is divided by a thin black line.

Male Azure Bluet. Notice that there are three blue segments at the tip of the abdomen (as opposed to two blue segments in the similar Skimming Bluet). 

Mated pair of Azure Bluets, photographed at Cox Arboretum. 

Another male Azure Bluet. This species is most common from May through September, although stragglers can persist into October. (My personal early and late sightings are April 29th and October 9th).  

Another female Azure Bluet. This species is common at Cox Arboretum, Grant Park in Centerville, and the Caesar Creek Wildlife Area. They live in fishless wetlands. 

Female Skimming Bluet, photographed at Fairborn Marsh. Notice that the blue square near the end of the abdomen is partially (but not completely) divided by a thin black wedge. Skimming Bluets can be found at several locations in our area, including Oakes Quarry and Spring Valley Wildlife Area. They tolerate the presence of fish better than many damselflies.