From your website it seems I have photographed a "Metallic Sweat Bee". This was taken 10/7/04 in West Greenwich Rhode Island. I have lived in this area for 40 years and never seen one. Is this appearance the result of the recent hurricanes?
Nice photo of one of the metallic sweat bees, probably the Virescent Green Metallic Bee, Agapostemon virescens. Yours is a female. Female bees have the abdomen ringed in white and males in yellow. They range from Quebec to Florida, west to Texas, and also Oregon. For nests, they dig burrows in bare and sandy soil. Adults drink nectar, but collect pollen to feed the young.