"Hole-y" cow...

While mowing my lawn recently, I came upon a large expanse of leaves that had fallen from the trees. As I mowed over them, I saw that there were some type of flying insects hovering very closely to the leaves. Since they flew away as I got close enough to get a better look, I figured they were flies and that they were circling some deer excrement. We have loads of deer in our yard, and as I mow I sometimes catch a whiff of what they leave behind. I didn't give it another thought.

On my way back up the hill, I looked to my right and noticed a very LARGE hole in the ground. I decided just then that I would not try to mow over it because the riding mower may get stuck. But, curiosity got the better of me and I had to find out what lived there. I put the mower in park and went to check it out. I figured that it must be a nest for some large rodent, probably a prairie dog, groundhog, etc.

As I approached the hole, I noticed there were a lot of those same flying bugs around the hole... but when I got closer, I quickly realized that they were not flies. Instead, there were smooth yellow and black bees zig-zagging all around the hole. When I got right over the hole, I realized it was a bees nest. There were hundreds inside the hole. I couldn't even tell how deep the hole was because of all the bees. I, of course, immediately got back on the mower and retreated.

I've never heard of a bees nest in the ground. I've seen them in trees, along buildings, in wood, but never in the ground.

Our neighbor keeps honeybees, and we had a hornets' nest in the trees about an acre down the hill in the front yard -- so my first thought is that the bees might be one of these two varieties. But the bees seem flat and smooth, not round and hairy. I have no idea what they are. If anyone can help me out here, I would be more than thankful. I'm very worried that they are yellowjackets.

I went back the the hole later and snapped a couple pictures. There weren't as many bees in the hole this time, but there were a couple and there were scads of them buzzing around me while I snapped away. I think the mower must have made them all retreat to the entrance, because there were so many the first time. Here's a picture of the hole, and a picture of the bees (if you can make them out. I zoomed in on one of the hole pictures to get a closer look.)



Help!