Why do bumblebees die after they sting you?

Honey bees don't bite they sting, and yes they do die after stinging, unlike wasps which will live to sting over and over again. The reason that honey bees die after stinging is because they cannot retract their sting barb which is an integral part of their body. ie, when the sting barb pierces your skin, the honey bee cannot withdraw the barb so its only method of escape is to leave the barb in your body, but the barb is such a large part of the bee's body that it cannot live without it and will be dead within a few minutes.