Three species of stored-product insect pests, Tenebrio molitor, Tribolium confusum, and Trogoderma parabile, were acclimated at three temperatures, 15°, 23°, and 30° or 33°C, and then placed in chambers containing an appropriate culture medium held at testing temperatures ranging from 3°C to 14°C. Cold-acclimated insects demonstrated greater dispersal at low temperatures than did warm-acclimated insects. Dispersal was greater at higher than at lower test temperatures. In a given species large larvae generally showed greater dispersal than did small larvae. © 1969.