American Dragon!!

I found this stunning American dragonfly today while walking along the sidewalk near the Mississippi river. There were two of them catching some rays on a low wall. They were quite friendly, and this one first got onto my finger when I offered it, and then landed on Charlii's back.
It is really beautiful, and unlike anything we get in the UK.
I also found a stunning hoverfly and numerous large wasps.
If any blippers have the id on this I would be most grateful, as I have no idea at all!!