In the 1970s, the bicyclic ketal endo-brevicomin was identified as a male-produced pheromone for the southern pine beetle, Dendroctonus frontalis. In coupled gas chromatograph-electroantennographic detection studies, we found that the (+)-enantiomer elicited antennal responses in D. frontalis at concentrations five orders of magnitude lower than the (-)-enantiomer and two orders of magnitude lower than this species’ aggregation pheromone, frontalin. Chiral GC-MS analyses of aerations/extracts of individual beetles indicated that D. frontalis produce only the (+)-enantiomer of endo-brevicomin. Data from field trials conducted with >99% pure endo-brevicomin enantiomers are presented. We reassess the original classification of endo-brevicomin as a multi-function pheromone for D. frontalis.