Obscure Bumble Bee

Description:

The obscure bumblebee is predominantly black, with yellow coloration on the face, top of the head, forward half of the thorax and on the fourth tergite (dorsal abdominal segment). The third and fourth sterna (ventral abdominal segments) have long, yellow hairs on their frontal rims. The head is rounded, with a medium length proboscis (tongue). (From Wikipedia)

Habitat:

The obscure bumblebee is an uncommon species, found near the western coast of the United States from Washington to California.

Notes:

This bumble bee was spotted in my front yard flying around the rhododendron tree in full bloom. This one was much bigger than the other bumble bees with orange color. I'm pretty confident with my ID, but I'm no expert, so any suggestions are welcome! I also used this reference: http://www.fs.fed.us/wildflowers/pollina...