Male aristae of laboratory reared Ceratitis capitata were longer, both in absolute terms and in proportion to body size, than those of females. Both male and female aristae had microtrichia which lacked membranes at the base, but female aristae had more microtrichia that were more evenly distributed than those of males. Female aristae also had more curves in the distal end. Experimental removal of female aristae resulted in less frequent mounting, and less copulation once mounting had occurred than in control females. Stimuli sensed by the female's arista may thus affect her readiness to copulate.