Any of several families of winged stinging insects of the order Hymenoptera, characterized by a thin stalk between the thorax and the abdomen. Wasps can be social or solitary. Among social wasps, the queens devote themselves to egg laying, the fertilized eggs producing female workers; the males come from unfertilized eggs and have no sting. The larvae are fed on insects, but the mature wasps feed mainly on fruit and sugar. In winter, the fertilized queens hibernate, but the other wasps die.

Of the 290 British species, only a few are true wasps, Vespidae; the rest are digger wasps. There are seven British species of social wasp in the genus Vespa, some nesting below ground, others in trees or bushes, the largest being the hornet; all the others are solitary.

Wasps evolved 200 million years ago in the Triassic period as stingless plant-feeders. By the Jurassic period, 50 million years later, they had developed the constricted waist, a sting, and become parasitic.

A stingless wasp thought to have become extinct 20 million years ago was identified 1995 as living in pine forests in the Sierra Nevada mountains, California. The 8-mm/0.3-in long wasp has an undivided thorax and abdomen, and is a member of the family Xylelidae.