I found this Bumblebee in a garden across the street from the U.S. Conservatory in Washington DC on June 21, 2009. I believe it is a worker Bee
Species Bombus pensylvanicus – American Bumble Bee
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon (Aculeata – Bees, Ants, and other Stinging Wasps)
No Taxon (Anthophila (Apoidea) – Bees)
Family Apidae (Cuckoo, Carpenter, Digger, Bumble, and Honey Bees)
Subfamily Apinae (Honey, Bumble, and Digger Bees)
Tribe Bombini (Bumble Bees)
Genus Bombus (Bumble Bees)
No Taxon (Subgenus Thoracobombus)
Species pensylvanicus (American Bumble Bee)
Queen 21 – 25 mm//Worker 14 – 18 mm//Male 16 – 22 mm
Queens have yellow fur on the forward part of the abdomen and the forward part of the thorax. The remainder is black and furry.
See detailed description of queen and male at discoverlife.org.
Eastern North America from Quebec to Florida; its subspecies (or a closely related species) sonorus occurs west to California.