Really Big Bee

This morning I had the door open to enjoy some late spring fresh air. We had a visitor enter the house. She is perished, alas, but she is also the largest bee I have ever seen. Tip-to-tip, unfolded, she is just over an inch long without including her stinger. She sounded like a humming bird.

She spent the day at the clerestory windows, except for one short descent down the wall. At sunset she alighted on my infant daughter’s monkey toy which is weirdly orange. Perhaps she was desperate for nectar. I noticed that she was no longer at the clerestory window from the staircase, but it took my dog sniffing wildly in her vicinity for me to notice where she’d gone. The next picture has a millimeter scale. It is hard to appreciate her size since she is curled inward.

Look again at her stinger and the drip of juice on it. I understand bumble bee stingers are not barbed which means that they can sting multiple times and that they do not die after stinging. On the other hand, they are not particularly aggressive.

I have tried to identify her species, but do not have a good key available. I got some help from Fortune Favors the Bold, where the closest match is Bombus fraternus. Please post an identification or a link to a good key if you know of one.