J. Chattin Reithrodonmys megalotis Columbia R. 300 ft, at mouth of Deschutes R, Sherman Co., Oregon July 2 6 field mice caught caught along fence line near edge of pasture. Vegetation cover of thick brush and willows on one side & grass and weeds in pasture (35 traps 10 yds apart) July 3 - 4 Reithrodonmys megalotis caught in same locality along edge of cultivated alfalfa field and willow thicket in 48 traps 15 yards apart. July 16 Maryhill, 200ft, Klickitat Co., Wash. 2 ♀ R. megalotis caught along bottom of dry wash, in vegetation of cheat grass, wild oats. Some scrubby bushes nearby. July 18 Paterson, 250 ft. Benton Co., Wash. 3 field mice caught in sandy soil near edge of dry abandoned field. 1♀ contained 2-6 mm. embryos. Aug 1. 2 mi. E Vinton, 490ft, Plumas Co., Calif 1♂ Reithrodonmys caught beneath sagebrush in sandy soil in line58 traps 10 yards apart.