Green Bees?

On a recent visit to Bolsa Chica, I spotted these tiny, metallic green wasps (I thought). They were fascinating, flashing in the sun, and I watched them for a while before taking a photograph which I, of course, posted on bugguide. It turns out that they are bees! There is such a thing as a metallic green bee.

Who knew?

Of course, now I want to know what the difference is between bees and wasps. If you'd asked me before, I'd probably have said that bees are chunky, fuzzy creatures and wasps are sleek, non-fuzzy creatures. But that, clearly, is not the difference.  And, since some bees are solitary and some wasps are social, their lifestyle doesn't help much either. Anyone got any ideas? Information? Links?