I'll have to do a bit of Googling to identify the facial structures: is that four eyes, or two? And if two, which two? (The forward ones, I think.)So I've done my homework, and here's what I've found out:
Bumblebees have 5 eyes. Or light-sensors, anyhow. They have 2 large compound eyes (which could be considered to be hundreds of eyes, I guess) and 3 ocelli, or primitive eyes that detect changes in light intensity.
Here's the photo again, cropped and labelled: (Click on it for a full-size view.)
The top two eye-like knobs on the thorax that confused me are the connecting points for the wings, which are almost invisible in this photo. The knobs that look like two smaller eyes are really the tops of the large, water-drop-shaped compound eyes. The antenna is attached part way down the length, in the space between the eyes, and crosses in front of the eye, which makes it hard to distinguish the shape of the eye in this photo.
The ocelli are the little bumps in the centre of the forehead. It looks to me, from the photo, that there are more than 3, but maybe this bumblebee just has a warty forehead.
I found this site, Bumblebee.org, packed full of useful information. Going down their menu, I found the mouth parts page, and identified the tongue on another of my photos. You can see it here, delving into the centre of the flower:
Bumblebee.org has a handy page on North American species of bumblebee, which I will be referring to often this summer, I think.
And while we're looking at bees, the latest Circus of the Spineless is up, and includes two great bee posts: Bees Knees, and Cellophane Bees. Good photos; go on over and look!