Journal Hafner, M.S. 1979 3 July (cont) 1 km N Siqueros, Son, Sinaloa, Mexico. The native habitat was “short-tree semi-tropical forest” with large legume trees and large candelabra-type cacti. The soil was extremely rocky. The Thomomys seemed to avoid the softer soils and were always found in rocky areas. 1930 we drove into Siqueros for some “refrescos” (cokes) and retired 2045. We had a miserable night... mesquitos, hot, dogs barking, light rain, ... etc. 4 July 1 km N Siqueros, Son, Sinaloa, Mexico 0530 awoke after little sleep. Checked traps - no captures. We each set out several more sets bringing a total of ± 20 sets. I captured 1 Thomomys at 0930, 1 at about noon, and one about 1600. John caught 1 at about 0830. We had several set-offs, but didn't catch any more than these 4 Thomomys all day. Extreme heat made it very uncomfortable. We washed-off in the Rio Presidio on occasion - the water must have been 85° F. We noted several types of iguanid lizards, ranging in size from that of a fence swift to large (ca. 18") iguanas. Many Cremidophorous snakes etc.