Chattin J. 1940 Itinerary Dec 23 (cont.) 7mi, S Palo Verde, 275 ft., Imperial Co. Calif. in fine drifted sand); 1 Neotoma lepida was caught near a "house" built about the base of an ironwood tree. 3 other N. lepida were caught by tearing apart their houses. The wood rats build their houses of dead sticks and branches which are plentiful in the washes. Houses are built usually in ironwood or mesquite trees and are placed either on the ground around the tree trunk or a few feet (2-5) up in the tree. Those placed on the ground consistently had burrows beneath the ground surface while rats building above ground took refuge in holes in the tree in or near the nest. In early p.m. Camp was moved to locality at 1 mi, NE Fort Yuma 200 ft., Imperial Co. Calif. 75 mouse traps and 8 rat traps were set out along canal banks where heavy growths of bamboo, bermuda grass, and arrowweed. Traps were baited with walnuts and set at intervals of about 10 faces. Dec. 24- (a.m.) Late yesterday evening and during the night there was moderate rain but drying wind in early morning dried off bamboo and grass before 9 a.m.- Traps were inspected and those sprung by mice or rain were reset. Catch consisted of 4 Sigmodon