P. PEARSON 1951-1952 Ctenomys opimus (cont) April 16 5 lam E. Jung-Luche: Returned to our census area and found what appeared to be 12 sets of recent diggings. Punt out traps in late afternoon. April 17 Shot 1 and trapped 3 trees on the census area, and 3 traps had hair in them. No fresh diggings appeared. Few dones on the census area, and ground tyrant. April 18 No fresh diggings, and no traps sprung on the census area. Collected dove (gold shoulder patches = Metriphlus?), ground tyrant (Muscicapulus flamineus?) and Phyllotius leucura on the census area. at 11:30 a.m. (air 55°) temp. in 2 burrows 8" below surface were 7° and 9°C. at 3:10 (air 52°) when ground absold [absorbed] bone warmed up most 2 tunnels registered 9° + 10°C. April 19 No fresh diggings on area, no traps spring. Took burrow temps at 5:30 when should be coldest: 3½° and 4°C. Highest diggings on way up Tintipoco were 15,800 ft. April 22 Still no new diggings on the area.