Although, I have been observing nature for over 50 years here in Oklahoma, I only saw this beetle once, about 25 years ago, when I moved into the ancient Crosstimber Forest.
It is a hummingbird mimic.
Almost the size of a hummingbird, this insect has an emerald green, elongated body.
It extended it's wing cover membranes out the rear and crossed them so they looked like the slightly forked tail of a hummingbird.
It's wings extended perpendicular from it's body just as a hummingbird's wings.
It kept it's proboscus extended straight to look like a hummingbird beak.
It hovered at a flower and then would fly backwards, leaving the flower and going to the next in perfect hummingbird fashion.
I watched this insect for over 30 minutes. I looked in reference books for years and never saw anything like it.
I did, finally, meet a man who lives about 4 miles from me that had seen one, once, also.
Anyone have an ideas?
It sounds to me like you have spotted a Hummingbird Moth or Hummingbird Clearwing(Hemaris thysbe)
I've seen a few when I was collecting butterflies as a child.
It seems they aren't very common in Oklahoma or Alabama(where I live)
Hope that helps.
I am familiar with those species but, no, this was an emerald green beetle much like Cotinis nitida (June Bug) only much longer. The description I gave is accurate. As I mentioned, the only other person I know of that has seen one, also, lives in this area of the Cross Timber Forest of central Oklahoma.
On Friday, July 9, my cat caught an insect that sounds exactly like the one you described. I thought she had caught a hummingbird and made her release it. It was big, definitely round and beautifully blue and green (sort of irridecesent, like a scarab). I know it wasn't a Hummingbird Moth because I saw one this weekend at Tyler Arborteum in Media and it is much more bird shaped, much more like a hummingbird, with fluffy fur-like stuff on its back. I'm sorry that I didn't keep it as no one seems to believe me. I have never seen anything like it before. To be honest, I'd never seen a Hummingbird Moth either.
So, it's refreshing that you saw the same thing.