I love the Internet. Yesterday afternoon I Googled "dragonfly" and found these folks. I emailed them the digital pictures of the visitor we had, and got a great reply. I'm told that what we had on our hanging basket was probably a teneral (young) Rhionaeschna multicolor (Blue-eyed darner), and I found this picture of an adult on the website:
Rhionaeschna multicolor - male, photograph by Greg W. Lasley
I'm also told that whatever it was, it was "certainly teneral, and that is why it stayed perched in the same spot for so long." I did get some really lovely shots yesterday with my SLR, which I will scan this afternoon (I hope). It's too bad it wasn't an adult - I love that blue head! - but the only reason it stood still long enough for me to get as many pictures as I did is because it wasn't an adult. It was pretty cool either way.
(Oh, and he wasn't there when I got home from work, so I'm really glad I stopped long enough yesterday to get pictures!)