I took this photo last year in Columbus. Note the nearly entirely black, shiny abdomen. Bumblebees (Bombus ssp.) have lots of yellow on the abdomen, which is mostly hairy. This individual was attempting to short-circuit normal pollination procedure, and eat through the base of this mint. Flowers with long corolla tubes can be difficult or impossible for the bee to access the pollen, so they eat their way in.
This shot is from last weekend, in Adams County. Note the male's whitish face, another field mark that distinguishes it from bumblebees, which have black faces. Look at the shape of this thing - it's like a tiny beer barrel with wings! No wonder the aeronautical engineers don't think large bees should be able to fly, at least on paper.
He was fiercely guarding a female, and it was a treat to watch. The bee would hover noisily on point, abruptly turning 90 degrees every few seconds. If any other winged insect happened by, it would be on the interloper instantly, and essentially fly right into it like some clumsy big-time wrestler. It'd even rush towards me if I got too close.
Apparently male carpenter bees are real studs, and once one has paired with a female, it has to constantly guard her lest one of the other boys make a play for her.
Eastern Carpenter Bees are a double-edged sword. They are very valuable as pollinators in the ecological web, and we need all of the pollinators we can get. On the downside, they can cause structural damage to the wooden features of buildings, as females drill sizeable holes and chambers in wood. Get enough of them drilling in the cabin for a long enough time, and some serious issues can arise.
At least we don't have to worry about the fiercely protective males stinging us.