To Bee or Not to Bee

A bee? Or Not? It might be a wasp. Down the street is a bunch of these plants called Centauria. They are very striking and photogenic and the bees love them. Whilst I was there, I saw three different nectar loving flying critters slurping up what they could from these flowers. I saw, I believe for the first time in my life that I can remember, a green metallic bee. Of course, the regular honey bee was there and then this guy. The image of the green thing almost made the blip, but I like how this one came out better. I tried to identify these critters, hence now knowing about green bees, and I couldn't find exactly a bee/wasp that looked like this one. Anybody else know what it is for sure?

Thanks!! Hoverfly it is! Never heard of it either. I'm obviously lacking in insect knowledge.

Wikipedia says:

Hoverflies, sometimes called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the larvae (maggots) eat a wide range of foods. In some species, the larvae are saprotrophs, eating decaying plant and animal matter in the soil or in ponds and streams. In other species, the larvae are insectivores and prey on aphids, thrips, and other plant-sucking insects.
Aphids alone cause tens of millions of dollars of damage to crops worldwide every year; because of this, aphidophagous hoverflies are being recognized as important natural enemies of pests, and potential agents for use in biological control. Some adult syrphid flies are important pollinators.
About 6,000 species in 200 genera have been described. Hoverflies are common throughout the world and can be found on most continent except Antarctica. Hoverflies are harmless to most other animals despite their mimicry of the black and yellow stripes of wasps, which serves to ward off predators.