I shook out a laying worker hive this morning, putting in its place a different hive with frames of open brood and nurse bees. I went back a couple of hours later and this little bee was hovering around and would occasionally land on one of the honey bees. I hope it is clear in the picture (the antennae are perhaps the feature which most differs from a honeybee), but it is NOT a honeybee. It is smaller, a littler darker, doesn't fly like a honeybee. . . yet it is most certainly a bee of some kind. Anyone know what it is? Or what it might have been doing?