These are outside a window in Phoenix, Arizona. I looked on the internet for pictures and these guys looked very similar to winged termites.
They could be halictid bees, possibly Agapostemon splendens.
Yours looks very similar to this picture
Compare the metallic head and thorax (that's the middle segment), the striped abdomen (the last segment), the apparent large size of eyes and place of antennae attachment, and the 'buff' hindlegs.