ONE of us (J. D. G.)—recently engaged in investigating the feeding habits of ticks at the Dominion Entomological Station at Kamloops, British Columbia, with special reference to the dissemination of disease—at the end of September, 1934, brought to the zoological laboratory at the University of Alberta, Edmonton, a limited number of adults of Dermacentor andersoni (native at Kamloops) for winter study. In contrast to their behaviour through the summer months, these ticks consistently refused to feed when brought to Edmonton in the autumn. Incidentally, one individual placed on a sheep at Kamloops, as early as the beginning of September, had refused to engorge and was finally removed after two weeks. This observation appears to agree with the experience of the Rocky Mountain Laboratory at Hamilton, Montana, where thousands of ticks are reared annually. FIG. 1. A. Adult female tick (D. andersoni) unfed. B. Engorged female, at the commencement of egg-laying, February 10, 1935. × 3.