Most bees or wasps only sting when provoked or threatened. Wasps and bees have venom sacs at the ends of their bodies, with a stinger that injects the venom into the victim. They can sting you even after they die. If you see a dead wasp or bee, do not pick it up: You can still get stung.
Wasp or Bee?
Wasps have a narrow waist; bees are rounder, with no waist. In flight, wasps' legs can be seen hanging down from their bodies. Bees' legs are not visible. Bees are fuzzier-looking than wasps, as they have fine hair on their bodies.
When a wasp stings, the stinger does not detach from the venom sac, so it can sting repeatedly. Honeybees die after they sting because their stinger remains in the victim.
How Stingers Work
A chemical in the wasp venom alarms other wasps, who then swarm the victim, particularly if it is moving. Even after a wasp dies, the venom sac continues to move for as much as an hour, and you can still be stung if you touch it.
Only female wasps have a stinger because the stinger is actually used to deposit eggs. Male wasps bluff and look like they're stinging, but can't. Visit the West Virginia University Extension Service for good information about wasps.
Wasps and bees can be a nuisance and their stings are painful, but they are beneficial insects nonetheless. Bees are pollinators, and wasps often hunt other insects that sting or bite.