Sex attractants for the geometrid moths Eufidonia convergaria and Caripeta angustiorata, and the noctuid moth Rivula propinqualis have been elucidated during field screening of a series of (3 Z,6 Z,9 Z)-triene hydrocarbons (C17-22), and the racemic and enantiomerically enriched monoepoxydienes derived from those hydrocarbons. Biologically active compounds were identified by a combination of field testing of synthetic standards, electroantennography, and coupled gas chromatography-electroantennogram detection. E. convergaria males were optimally attracted by a 1:1 blend of (3 Z,9 Z)-(6 S,7 R)-epoxy-nonadecadiene (3 Z,9 Z-6 S,7 R-epoxy-19:H); other abbreviations follow the same system) with (3 Z,6 Z,9 Z)-nonadecatriene (3 Z,6 Z,9 Z-19:H). The 6 R,7 S enantiomer of the epoxide had no apparent biological activity, either as an attractant or as a behavioral antagonist. Male moths also were attracted to blends of the C18 and C20 homologs of the triene and the epoxide. 3 Z,6 Z,9 Z-19:H and 3 Z,6 Z-cis-6,7-epoxy-19:H were identified in E. convergaria female pheromone gland extracts. Males of the geometrid moth species C. angustiorata were attracted by a 1:1 blend of 3 Z,6 Z,9 Z-19:H and enantiomerically enriched 3 Z,9 Z-6 R,7 S-epoxy-19:H. Males of the noctuid moth R. propinqualis were attracted by an approximately 10:1 blend of 3 Z,6 Z,9 Z-19:H and enantiomerically enriched 3 Z,9 Z-6 S, 7 R-epoxy-19:H. The components were synergistic, with neither being attractive alone. The blend ratio was quite specific, as the attractiveness of blends decreased sharply on either side of the optimum ratio. © 1990 Plenum Publishing Corporation.