JESimpson, 1938. 69. 270± ft., Rancho de Costa Rica, Rio Sonora, Sonora. May 3, 1938, continued. taken in the fields but common outside, and the harvest-mice were not at all found at field- borders but the most common mouse in the corn and wheat fields. Put up specimens and then repaired the bat- trap by putting wires more taunt and closer (1') to water in effort to get the early flying pipistrels. The we got 1 mastiff bat, 3 brown bats, and 8 Mex- ican free-tail bats, we caught no pipistrels. May 4, 1938 Put up the brown bat series and the remaining three mastiff bats which all were kept alive since night of May 2, 1938. Many of the Mexican freetails had escaped; the remainder were freed. The specimens of May 2, 1938: Eptesicus fuscus: ♂ 300- 304, 305, 308: no emb. 303, 306-7 and ♀ 275, [illegible], 277, and Eumops perotis: as skeletons only: ♂ 309, 310 and ♀ 311. One additional mastiff bat Dr. Benson took from the trap in the morning; probably in tank all night having been trapped after we retired. This bat was in sad condition—wet and appearing fatigued and half-drowned; it was hung on a cloth under our camp-mesquite tree where we watched it while working on specimens yesterday. The bat dried, but continued to hang in camp—responding viciously to Mexican teasings— until dusk when it showed some life and finally took