There is only one queen in a hive and her main purpose in life is to make more bees. She can lay over 1,500 eggs per day and will live two to eight years. She is larger (up to 20mm) and has a longer abdomen than the workers or drones. She has chewing mouthparts. Her stinger is curved with no barbs on it and she can use it many times.
Drones, since they are males, have no stinger. They live about eight weeks. Only a few hundred - at most - are ever present in the hive. Their sole function is to mate with a new queen, if one is produced in a given year. A drone's eyes are noticeably bigger than those of the other castes. This helps them to spot the queens when they are on their nuptial flight. Any drones left at the end of the season are considered non-essential and will be driven out of the hive to die.
Worker bees do all the different tasks needed to maintain and operate the hive. They make up the vast majority of the hive's occupants and they are all sterile females. When young, they are called house bees and work in the hive doing comb construction, brood rearing, tending the queen and drones, cleaning, temperature regulation and defending the hive. Older workers are called field bees. They forage outside the hive to gather nectar, pollen, water and certain sticky plant resins used in hive construction. Workers born early in the season will live about 6 weeks while those born in the fall will live until the following spring. Workers are about 12 mm long and highly specialized for what they do, with a structure called a pollen basket (or corbiculum) on each hind leg, an extra stomach for storing and transporting nectar or honey and four pairs of special glands that secrete beeswax on the underside of their abdomen. They have a straight, barbed stinger which can only be used once. It rips out of their abdomen after use, which kills the bee.