Optical isomers of pine sawfly sex pheromones, the acetate and propionate esters of 3,7-dimethylpentadecan-2-ol, were tested in the field and by electroantennograms (EAGs) for activity toward four species or species complexes of fall-flyingNeodiprionsawflies (Hymenoptera: Diprionidae):Neodiprion pratticomplex,Neodiprion taedae linearisRoss,Neodiprion nanulus nanulusSchedl, andNeodiprion sertifer(Geoffroy). Traps baited with the acetate of the 2S, 3S, 7S isomer caught males in all cases. The propionate form of this isomer was active in all cases exceptNeodiprion pratti pratti.N. p. prattiwere caught in traps baited with the propionate of the 2S, 3R, 7R isomer. The 2S, 3R, 7R propionate isomer elicited the greatest EAG response fromN. p. prattiantennae, whereas the 2S, 3S, 7S acetate isomer was most active with the other species.