none A multicomponent sex pheromone in Macrocenntrus grandii Goidanich (Hymenoptera: Braconidae) was demonstrated using wind-tunnel and field bioassays. In wind-tunnel bioassays, three Florisil fractions from female wasps (hexane, 5%, and 50% ether in hexane) and one from male wasps (50% ether in hexane) were attractive to males. The hexane and 5% ether in hexane fractions each elicited similar male behavioral responses. These included upwind anemotaxis, casting, landing on the source, wing fanning, and mating attempts between males. The 50% ether in hexane fraction, whether male- or female-derived, initiated a strong flight respionse by males but few landing on the source. In addition, the 50% ether in hexane fraction was found to synergize strongly the hexane fraction. All females tested in the wind tunnel gave no responses to male- or female-derived extracts. Field tests generally supported the wind-tunnel results, although no field attractions was observed for the 5% ether in hexane fraction.