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For Insects, Spiders & Their Kin
For the United States & Canada
Damselfly - Enallagma anna

Damselfly - Enallagma anna
Yellowstone, Park County, Wyoming, USA
July 20, 2006
If you look closely, you can see some parasites underneath.

Moved from American Bluets.

Not sure
To me it looks most like River Bluet, except for the pattern on S2. They are somewhat blurred, but the cerci look pretty long to me. The black on S2 might be the result of some variation that is not mentioned in the books.

Ah! Thanks Cliff
E. anna certainly had tempted us. Looks like we almost made it to the right ID, just erred in that last choice. Thanks for looking at this and thinking about it.

And after all that -
now to the ID. We would propose this as a damselfly in the genus Enallagma. Luckily there aren't too many with the color pattern consisting of a mostly blue abdominal segment 3 changing gradually on each successive segment to an almost entirely black segment 7. And most of those are eastern species. The wide black shoulder stripe on your image eliminates E. clausum. Which leaves us with E. anna and E. carunculatum. E. anna should have noticeably huge claspers on the male and should be almost equally blue and black. Abdominal segment 5 would be about half and half black and blue. So we will suggest this is E. carunculatum with its smaller claspers and with more black than blue on the abdomen - segment 4 is the half black half blue one.
We must add one caution - the black color pattern on segment 2 with black color coming down and then forward is typical for the genus Coenagrion, but we don't know of one with so much blue on segment 6. C resolutum should have none there and a green thorax, while C. interrogatum should have some blue on the back end of segment 7. That's why we're choosing Enallagma, but we must admit segment 2 bothers us!
This is a fascinating beast! It will be interesting to see what Cliff has to say. Thanks for posting such a remarkable specimen.

Thank you!
Thanks a lot for all your trouble!

No deletion of comments
You can edit your comments if no one has replied to them. We deliberately did not reply to your second comment here so you can see the difference. You'll notive your first comment only shows an option to reply, while your second shows both an option to reply and an option to edit. The purpose, of course, is to make sure any replies to any of your comments continue to make sense. If someone replied to a comment and then you changed your comment, the reply might become confusing. We are always hopeful that some group of editors will be given the ability to delete comments that no longer are important for BugGuide. The four comments here could easily be deleted without affecting the true value of BugGuide. But for right now, no one but John VanDyk can delete comments and individuals can't edit their comments after someone replies directly to them.

Sorry, wrong location. Yellowstone Wyoming. I'm so used to typing in Texas I forgot.

Just click on EDIT and you can change
any of the information you submitted originally -- even the image!!

Thanks I didn't know that. Is there any way to delete comments?