beautiful bees

I need a better insect guide. The bees I saw were not Agapostemon virescens because they were entirely metallic green, no abdominal black-and-yellow. All the Audobon Society guide gives me is that or Augochlora species, which aren't supposed to live here. I'm guessing female Agapostemon because I saw two on the same flowers, which is some evidence for gregariousness, and the range for the whole genus seems to be US-wide.