JESimpson, 1938. 79 1150ft., SanJose de Gracia, 20 mi. NE. Hermosillo, Sonora. May 18, 1938. Tho the trapline was very similar to the ones at Costa Rica Ranch, and it was hoped that Perognathus flavus and some Reithrodontomy might be taken as at that Ranch; however, the trap-line yielded not one mouse. The ants had eaten most of the bait in about half the traps, but that doesn't account for the zero catch. The field was river-bottom land and is, of course, subject to periodic flooding; however, similar conditions existed at Costa Rica Ranch. Senor Delgadillo set at border of this field and caught only 3: 2 pocket-mice and a kangaroo rat. Broke camp and drove: to Gavilan to Guadalupe to Ures to La Pitaya to Bamuco to Alamos to a ranch, La Estancia, and made camp: 2150ft., La Estancia, 6 mi. N. Nacori, Sonora. May 18, 1938, continued. Set 44 mousetraps on grassy hill among trees, brush, and granite outcrops; set 50 live-traps around border of wheat-field which was border by mesquite, grass, and brush. These 50 live-traps were set between the 50 mousetraps here set out by Dr. Benson — mousetraps vs. live-traps again. By the field- bordering, brush-stacked, barbed-wire fence I noticed three sharpened sticks, point (at an acute angle off vertical) toward the top of the fence. One of the ranch boys confirmed suspicions that the sticks were set there as a deer trap — claimed to have stuck in ground and