In our earlier study of the female sex attractant from an arctiid moth (Utetheisa ornatrix), the occurrence of an uncharacterized C-21 tetraene was noted along with (Z, Z, Z)-3, 6, 9- heneicosatriene, the major pheromone constituent. The sex attractant glands of females from other populations of this moth have now yielded this (2-21 tetraene as a major component, accompanied by a new C-21 diene. Spectral and chemical studies of these ...