In adult populations where females are in excess of males, the ability of the males to mate more than once is an imporcant consideration when predicting the descendant population. Pointing (1961) found that under insectary conditions Rhyacionia buoliana (Schiff.) males are capable of inseminating mlore than one female. Stehr (1954) srates, with reference to a method of mating Choristoneura fumiferana (Clem.) in the laboratory, “Aftcr mating, the male may be discarded; only rarely will it mate succesfully with a second female.” During genetic studies conducted in an insectary on the reproductive capacity of four species of Choristoneura, a technique was used in which individual males were mated to several females. The purpose of the study was to gain genetic information and not to measure sexual activity so that maximum mating opportunities for che males were not provided. In the light of Stehr's observation, it was decided to publish these results since they provide valid but limited information concerning the polygamous capabilities of Choristoneura males.