The meadow jumping mouse, Zapus h. hudsonius Zimmermann, is generally regarded as one of the more profoundly hibernating mammals. It retreats early into its winter quarters, and returns to activity when spring is well advanced. Indications are that males emerge first in the spring, and that the date of emergence usually comes in April or May. This was the situation in Vermont as reported by Sheldon (Jour. Mamm., 19: 332, 1938). In Minnesota, Quimby (Ecol. Monographs, 21: 81, 1951) reported males as first emerging in late April or May, and females two or three weeks later. In several instances jumping mice have been excavated from their winter quarters, still in a torpid condition, on various dates throughout the month of April. Selected examples are cited in New York by Eadie (Jour. Mamm., 30: 307, 1949), in Missouri by Schwartz (ibid., 32: 228, 1951),...