A wasp is any insect of the order Hymenoptera and Suborder Apocrita that is not a bee or an ant. Less familiar, the Suborder Symphyta includes the sawflies and wood wasps, which differ from the Apocrita by having a broad connection between the thorax and abdomen. Also, Symphyta larvae are mostly herbivorous and "caterpillarlike", whereas the Apocrita are largely predatory or parasitic.
Most familiar wasps belong to the Aculeata, a division of the Apocrita whose ovipositors are modified into a venomous stinger that includes ants and bees. In this sense, the species called "velvet ants" (Mutilidae) are actually wasps.
A narrower meaning of the term wasp is any member of the Aculeate Family Vespidae. This includes the yellowjackets (Vespula, Dolichovespula spp.) and hornets
(Vespa spp.).
Wasp Characteristics
The following characteristics are present in most wasps:
Two pairs of wings (exception: female Mutillidae)
A stinger (only present in females because it derives from the ovipositor)
Few or no hairs (in contrast to bees); exception: Mutillidae
Predators or parasitoids, mostly on other insects; some species of Pompilidae, such as the tarantula hawk, specialize in using spiders as a host
Wasps are critically important in natural biocontrol. There is a wasp species that is predator or parasite upon almost every pest insect species. Wasps are also increasingly used in agricultural pest control.