Several different kinds of insects can cause serious allergic reactions:

Bees

The most common cause of an insect allergic reaction is the honeybee. Bumblebees and sweetbees are two other types of bees that occasionally (though rarely) cause allergic reactions. Bees will die once their stingers are removed from their body. Most bees are not aggressive and will only sting if provoked. Africanized honeybees (commonly known as "killer bees") are more aggressive.

Vespids

This group of insects includes hornets, yellow jackets, paper wasps, and other types of wasp. Vespids do not die when they sting, and can be more aggressive than bees.

Ants

Fire ants and Harvester ants are two types of ants that can cause allergic reactions. The red imported fire ant, originally native to Brazil, is now prevalent throughout the southeastern United States, especially in the Gulf Coast states. Large groups of fire ants will attack a human (or other animal) that steps on their hill or mound.   

Other insects

Although rare, there have been reports of allergic reactions to deer flies, bed bugs, and mosquitoes.

Learn more about identifying stinging insects.