A cat is as fascinated by a bee or wasp in flight as by any other small, moving object and may swat at the insect and get stung in the process. While a healthy cat isn’t likely to die from such a sting (though it is possible), the owner should try to locate the stinger and remove it using fingernails or tweezers.
A paste made of water and baking soda can help relieve both the pain and the swelling. Some cats, like some humans, are allergic to insect stings, and this will be evident if the swelling from the sting doesn’t go away soon. As with allergic reactions in humans, this immediately requires medical attention.