Bluets - genus Enallagama

Note - most of my Odonata research relies on Denis Paulson's great guides, The Dragonflies and Damselflies of the West -- and of the East).

The bluets are members of the genus Enallagama, the American Bluets, and I blame them for discouraging me from exploring more deeply into the damselfly suborder. I learned early on that many bluet species are similar in appearance and often cannot be accurately identified unless they are captured and examined with a hand lens, not something I do when birding.

There are about 37 American Bluets in the US, 25 of them seen in the "west", and 33 in the "east". I checked all my nature photos (25,000) and found that almost all my bluets were tagged as "bluet sp.", reflecting my failure to learn how to sort them out. I took a few shots of bluets on our Florida trip in early April, at the same pond where we found the Eastern Amberwing.  Yesterday I decided it was time to take the plunge and see if I could learn more. 

Here's the first shot, from a pond in Palm Harbor, FL. Looks like a "typical bluet", a damselfly with blue/black eyes, blue and black stripes on the thorax, and a variable pattern of blue and black on the 10 abdominal segments. Here the abdomen pattern is more blue than black, until you get to the 7th segment, which shows more black than blue. S-8, S-9 and S-10 are mostly blue, with some black on S-10. The wings are held to to side of the body, as with most bluets. Immediately behind the eyes there appears to be a pale blue line, in the area where one sees the post-ocular spots on a damselfly. Note also that the terminal appendages at the end of the abdomen appear quite small.

Nearby I photographed another bluet, perhaps the same species. The thorax stripes and the pattern of black and blue on the abdomen segments is quite like the first photo. The appendages here look a bit larger (different perspective?) and the post-ocular spots, now more visible, seem to form a dumbbell shape. You can get a better view of these photos by going the link to my Flickr photos , then clicking on the photo there to enlarge it.

Next I consulted Paulson's book on the Dragonflies and Damselflies of the east, focusing on the bluets. The range maps for each species were a good starting point, and it showed that there were only about 10 Enallagama species found in central Florida west of Tampa Bay. Of these 10 the color of the thorax and the pattern of black/blue on the abdomen quickly eliminated 7 species. That left only Big Bluet, Familiar Bluet and Atlantic Bluet. Hey, it's easier than I thought! I eliminated Big Bluet in part because it favor large lakes, but mostly because the black rings on the big extend forward more along the top of the abdomen segments. The Familiar and Atlantic Bluets share the same pattern on the thorax and abdominal segments. In Familiar the post-optical spots are usually not joined in a line or by a bar, so I favored Atlantic Bluet as the ID. The Atlantic also favors small ponds.

Looked though my older bluet photos and found this one, which I thought was probably a Familiar Bluet, from Marin County, CA. Note the larger terminal appendages, as well as the how the post-ocular spots are not connected by a bar. I'm not real confident with my conclusions and would welcome a review by more experienced eyes.