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Showing posts with label bluets. Show all posts
Showing posts with label bluets. Show all posts

Friday, June 10, 2011

northern bluet ~ 06/10/11 ~ Pinnacles

northern bluet
Enallagma annexum (formerly E. cyathigerum)

So much for looking at wing position to distinguish bluets (Enallagma spp.) from dancers (Agria spp.). Supposedly bluets have wings held close to the body, whereas dancers hold their wings up and away from their abdomens. Here's the second time where my pictures show the exact opposite of this. I've used the advice given by Jim Johnson at Northwest Dragonflier and Odonata.Bogfoot.net from my previous vivid dancer post to look at the color of the last (i.e., 10th) abdominal segment, at least in western damselflies. If it's mostly black on top, it's a bluet, and if it's all blue, it's a dancer. Again, another one of those naming things that doesn't mesh with what I now know to look for.

There are 4 Enallagma spp. reportedly found at Pinnacles: E. annexum, E. civile (familiar bluet), E. carunculatum (tule bluet), and E. praevarum (arroyo bluet). I ruled out the tule and arroyo bluets, because their abdominal segments are mostly black. I then ruled out the familiar bluet, because it has smaller eyespots and a triangular "fin-shaped" appendage at the tip of the abdomen. Finally, there is the possibility this could be an almost identical boreal bluet (E. boreale), but the distinction is in the tiny cerci (compare b with e) and not anything I can tackle with my point-and-shoot. Now, as before, I could be totally wrong with this ID. Jim?

The second picture above is a cast exoskeleton (aka exuvia) from a damselfly naiad. I love how they hug the tule/bulrush, something I'm not going to try to ID. What would damselflies do if there wasn't any tule around to hug?