I've seen green bees before, but they usually buzz off before I can grab a photo. Right now though (October), my Wild Poinsettia is attracting them. I have a giant clump of it that I let grow to hide an Australian Pine Tree stump, and these beautiful green bees are all over it.

They're as neat looking as bees get, so I chased them with my camera for a while.

If you want to know more about green bees, this site will help you figure out which species they are. Mine appear to be Agapostemon sericeus, splendens, or virescens. Perhaps when I finish with my butterflies, I'll go back and figure these out.

There's a neat bee discussion where I'm hoping to get an ID on these cool green bees.