I found a large bee on the street -alive. At first glance, I thought it was a Carpenter Bee, but on closer inspection, the abdomen seemed to have yellow bands, rather than solid black. However, looking even closer, and puzzled as to why the bee did not fly, I discovered that the "extra yellow" on the abdomen belonged to another bee, much smaller, that had taken hold of the larger one in a vice-grip, and would not be dislodged, even though the larger tried to fly off. I thought at first it was parasitism, but on inspection of the photos, I can see it may be a mating attempt. What do you think? The larger bee did not seem to be very accepting, and could not fly. It kept pushing its abdomen into the ground (avoidance). However, I think the hanger-on may have finally succeeded (final photo).