The American bumble bee (Bombus pensylvanicus) is very large (0.6 to 1 inch long). It has a black head, thick black band on a yellow thorax and yellow bands on the abdomen.
The rusty patched bumble bee (Bombus affinis) has a rusty-colored patch of hair on its abdomen, black head and yellow thorax with a black pattern that resembles a thumb tack.