Virescent Green Metallic Bee (Agapostemon virescens)
Virescent Green Metallic Bee (Agapostemon virescens), Des Moines County, Iowa
This bee was looking for nectar on a coneflower in a residential garden in Des Moines County, Iowa.

Details: 

Canon EOS 10D,  shutter 1/180 second, aperture f16, ISO 200, Canon EF 100 mm macro lens, Canon MR-14EX flash.
 

Selected References:

Borror Donald J, White Richard E. A Field Guide to Insects. New York: Houghton Mifflin Company, 1970. P 356-357.

Milne Lorus, Milne Margery. National Audubon Society Field Guide to Insects & Spiders. New York: Alfred A. Knopf, Inc., 1980. Plate 517, P 852-853.