Campoletis sonorensis (Cameron) males exhibited 4 main elements of courtship behavior when exposed to females or odor-laden air from females. The 4 courtship behavioral elements were: orientation, wing vibration, antennal touching, and attempted copulation. Odor from females lowered the threshold for the behavioral elements of courtship exhibited by males. Wing vibration may aid the male in orientating toward the odor source. Actual orientation of the male to another insect appeared to involve sight, while antennal touching was used by the male to position itself with respect to the female. Orientation and attempted copulation with males occurred as readily as with females in the presence of the female pheromone. Both virgin and mated males responded to both virgin and mated females. Multiplemated older females were less active in eliciting male courtship behavior. No region of the female could be isolated with respect to pheromone production. Ethyl acetate extracts of females were active in eliciting the courtship behavior of males.