I have bees in my yard (in southern Wisconsin) that look much like honeybees, maybe with less yellow.  They crawl out of little holes in the ground and never seem to swarm.  We've never had a sting, either.

Do you know what they are?  Do Mason bees nest in the ground?  (I've heard of putting up little straws in a bundle to encourage them to stay near your trees.)

We have three apple trees, two cherry trees, and a peach tree, so I'd like to encourage these guys. . .