JESimpson,1938 53. 950±ft, 5mi. sw Las Alesnas, 23 mi. wsw Caborca, Sonora. April 20, 1938. On the rocky hill caught 4 Peromyscus evemius (σ7206, +3♀emb), 7 Perognathus intermedius (σ7207,208,209,210; ♀211,212,213,emb.), 5 Neotoma lepida (σ7203,204; ♀205; all infected by bot-fly larvae). Shot a lizard in the sand (214). Shot a Gambles Quail for table. Broke camp and drove over sand and silt to Gulf of California at: 20±ft. Puerto Lobos, Sonora. April 20, 1938, continued. The fishing village here is very small (only ½ dozen or so shacks) and dirty. The truck drivers told us that there was no road from here to Puerto Libertad, contrary to information given in Caborca. Made camp at edge of sand dunes. Set 50 mouse- traps and 50 live-traps in sand dunes which are sparsely covered with tarote, a low-growing, dense bush, and some cholla. The sand dunes covered this area to the base of the hills which are 2-4 mi. inland to the ne but come down to the beach farther south on the bay and coast. April 21, 1938. Caught 1 Perognathus longimembris (♀215) and 4 Onychomys torridus (σ7216,217; ♀218,219). σ7216 was moulting. Many of the mousetraps were robbed by the "light- footed" pocket mice and beetles. Catalogued a lizard (220) shot on sand dune by Señor Delgadillo. Tried to go fishing but no bait available; so were satisfied with a bath in Gulf; broke camp and drove to: