Peterson 1935 Microdipodops megacephalus July 6. Marys River, 5800ft., 22 mi. N Deeth, ELKO Co., Nevada. 4 caught on gravelly slopes & E of Marys River. Claim, with some observational support, that Microdipodops most likely to be found in more sandy or fine gravelled patches or areas of terrain. Yet, they may be caught most anywhere in a gravelly region covered with sage brush, perhaps more truly if no sandy areas or sand dunes are in the vicinity. July 7. Marys River, 5800ft., 22 mi. N Deeth, ELKO Co., Nevada. One caught in same locality & type of country as above. Ectoparasites not noted, no endoparasites. July 9. Marys River, 5800ft., 22 mi. N Deeth, ELKO Co., Nevada. Two caught by Mr. Baldwin on dry gravelly slopes & E of Marys River, + prepared by myself. July 10. 15 mi. S Contact, 5800ft., ELKO Co., Nevada. One caught at base of slope covered with sage brush. Kind for one in trap at bottom of sandy wash in gulch.