Some male carpenter bees (Xylocopa spp.) possess massive propodeal exocrine glands that produce copious quantities of multicomponent blends of lipoidal material. Some of these compounds are volatile, producing a "flowery" aroma that can be easily detected several meters downwind from a territorial male. Chemical characterization of these secretions showed them to be blends of terpenoid compounds or fatty acid derivatives. InX. varipuncta, the mixture is composed of alltrans-geranylgeraniol, alltrans-farnesal, and an isomer of 3,7, 11-trimethyl-2,7,10-dodecatrienal in an approximate 9∶6∶1 ratio. The secretion ofX. micheneri contains isopropyl oleate, (Z)-11-eicosen-1-ol, oleyl alcohol, and methyl palmitate at approximately 63∶24∶11∶1. We hypothesize that these compounds act as pheromones that aid in attracting and holding conspecific females to symbolic nonresource encounter sites where mating occurs. They also appear to have utility as chemotaxonomic markers at the subgeneric level.