E.V. Miller 1940 Thomomys umbrinus May 3 11,000 ± ft. N slope Popocatepetl, Mexico. Took a ♀ in a gopher trap in the afternoon. Small mounds from 6 inches to a foot in height were numerous near our camp. The soil is fine, dark, and sandy. A few pine trees grow here, and the ground is nearly covered with large bunch-grass. The tunnel where this specimen was caught was about 20 inches below the surface of the ground. May 18 6 m. S E Punta, Jalisco. Took one female with 3 embryos in a gopher trap. There were 6 or 20 mounds near the place of capture of this specimen, each mound 6 in. to a ft. high and a ft. to k ½ ft. across at the base. The soil was very hard and dry and the only plant near was a small bush. Nevertheless this gopher was very fat.