Hoffmeister 1942 Peromyscus boylii May 17 Walker Cr., 4 mi. SW Blancha, 5200 ft, Dwy Co., Cal. Have caught this species in numerous localities here. Caught it in the Artemisia, Chrysothamnus, Lupinus association along Walker Creek (but not in this association at any distance away from the creek), beneath oaks and pines, and even at the base of rock slides, and among willows along the creek near the water's edge. Nearly all the adult ♀ are pregnant or lactating. In all 20 for examined the number of embryos has been 4. One was caught last night, in camp, in a baited mouse trap at 8:30 p.m. (this is war time or 7:30 p.m. standard time). May 19 One juvenile caught at the edge of camp at 9:45 p.m. (war time; 8:45 standard). May 20 In 1 trap the distal 1/4 inch of the tail only was caught. In another trap 150+ feet away there was a boylii with this exact amount of the distal end of its tail missing. This may indicate the distance covered, in part at least, by 1 mouse during the night.