Crosses between Tribolium freemani, recently rediscovered from imported corn in Japan, and T. castaneum produced many infertile F₁ hybrids. Weights of hybrid pupae were intermediate between those of parents, and the weight ratio between the sexes differed in the two parental crosses. The optimum conditions for development of T. freemani were similar to those of T. castaneum but the developmental period was slightly longer. The ease with which T. freemani was reared on wheat-feed medium suggests that it could become a pest of stored products. However, the absence of records of this species since late last century suggests that it is, at present, of negligible economic importance or extremely localized.