The bumblebee body can be divided into three main parts to make
identification easy. These are:
The head, which can be quite
difficult to see on a foraging bee as it is deep in the flower.
The thorax which has the wings and legs attached. It is
really just a box of muscles. The biggest being the flight muscles.
abdomen which has the honey stomach for storing nectar, the sting, the
wax glands and all the digestive and reproductive organs. For more details on bumblebee anatomy click on the BODY tab above left or here.
Bombus impatiens is one of the more common North American bumblebees.
Bombus impatiens licking honeydew
On the right you can see a worker with her tongue extended. There is no flower, so she is probably licking up honeydew excreted by aphids.
Bombus impatiens defensive behaviour
The photograph on the right shows the typical pose of a bumblebee who is not happy about something.
In this case it is probably the closeness of the camera, or it could be human breath (they don't like mammal breath), or both. The raising of one of the middle legs is always a sign to back off - the bumblebee won't sting, but it is disturbed by your presence.
Quite often if you back off and then move closer very slowly they will tolerate you. Also it is a good idea not to breathe too heavily, or to breathe to the side as mammal breath is not something they like. It is an instinctive thing as the only mammals that get this close are ones that are about to eat the bee or break into its nest.
Bombus impatiens mating
On the right is a photograph of mating. The queen is in front and the male behind. Males are usually smaller than queens. There is more about mating on the mating page.