The adult cicada killer is a very large (1-1/8 to 1-5/8 inches long), robust wasp with a black body marked with yellow across the thorax (middle part) and on the first three abdominal (rear part) segments. The head and thorax are rusty red and the wings russet yellow (brownish). Legs are yellowish. Coloration may resemble yellow jacket wasps.
Overwintering occurs as a mature larva within a leathery, brown cocoon in an earthen cell. Pupation occurs in the spring lasting 25 to 30 days. Adult wasps emerge about the first week in July. Emergence continues throughout the summer months. Adults live about 60 to 75 days (mid-July to mid-September) while they dig new nesting holes (burrows) in full sun where vegetation is sparse in light, well-drained soils. Eggs are deposited in late July through August. Eggs hatch in one to two days and larvae complete their development in 4 to 14 days. There is only one generation per year.
Solitary wasps (such as a cicada killer) are very different than the social wasps (hornets, yellow jackets and paper wasps). Cicada killer females use their sting to paralyze their prey (cicadas) rather than to defend their nests. The female wasps are non-aggressive and rarely sting unless touched, caught in clothing, disturbed by lawn equipment, etc. Though males aggressively defend nesting sites, they have no sting. Adults feed on flower nectar and sap exudates.
These wasps are commonly seen in late summer skimming around the lawn, shrubs and trees searching for cicadas. Cicadas are captured, paralyzed by a sting and used for food to rear their young. After stinging a large cicada, the female wasp drags it up a tree, straddles it and takes off toward the burrow, partly gliding. When trees are not available, the cicada (prey) is dragged to the burrow on the ground. Cicadas are very large insects, sometimes called "locusts." They sing loudly (noisily) in trees during late summer.
There may be many individuals flying over a lawn, but each female digs her own burrow six to ten inches deep and one-half inch wide. (They do not nest together.) The soil is dislodged by her mouth and loose particles are kicked back as a dog would dig. The excess soil thrown out of the burrow forms a U-shaped mound at the entrance, causing unsightly mounds of earth on the turf. This ground-burrowing wasp may be found in sandy soils to loose clay in bare or grass covered banks, berms, hills as well as raised sidewalks, driveways and patio slabs. Some may nest in planters, window boxes, flowerbeds, under shrubs, ground cover, etc. Nests usually are made in the full sun where vegetation is sparse, especially in well-drained soils. Occasionally they establish in golf course sand traps. (A very gravelly or bare area is preferred.)