A statistical analysis of U.S.DA. studies of insect attractants provides the first direct evidence for the reality of "primary" odors (heretofore inferred indirectly from abstract principles). Molecules of a single substance may carry more than one primary osmic character and the presence of one does not preclude another, but some primaries may overlap others. Thus the molecular qualities responsible for osmic properties appear to be distributed along a continuum. Molecular vibrational frequencies are so distributed, and the far infrared absorption spectra of some attractant and non-attractant substances show correlations of the sort predicted by the theory.