Adult H. postica (Gyllenhal) (Coleoptera: Curculionidae) from populations in Utah and Maryland were marked for recognition, placed in a free-choice mating situation, and observed repeatedly for 2 months. No mating preferences were shown, and eastern and western males were equally competitive in mating when they were confined with eastern females only. Sex ratios of progeny and egg hatch weie essentially as expected from previous single cross matings—an increase in the ☥:♂ sex ratio of progeny from western ☥ ✕ eastern ☥ matings and complete sterility of eggs from eastern ☥ ✕ western ♂ matings.