Koford 13 Cynomys ludovicianus January 6, 1955. Nr. Ft. Collins, Colorado. found a four troche stop & mound of 3 only; there 3 was maked with atobar. Apparently C13, C7, and a small mound 30 yds. E. of Ms. Troche for large dog (Canis) visited several burrow mouths. No C.L. activity at many holes that had troche before. None connecting burrows on surface. January 8, 1955. At about 4 p.m. visited Spring Camp, Den colony. With exception, eaten burrow about 50 yds. NW of C13, no new prairie dog troche at burrow. Many more rabbit troche than Jan. 6. Cold & partly overcast today; probably < 30°F. all day. Apparently stay under- ground for at least 3 days when cold after snowstorm. [Weather remained cold; somewhat warm Jan. 11,12, but <40°F.] Paul Baldwin told me he saw large colony near U.P.R.R., near Cheyenne in late December. January 12, 1955. 8 mi. N. of Niwot, Weld Co., Colo. Visited colony that B.C. Klyeyle had showed me in Central Bair's Cyp. Range. Colony in NE¼ of SW¼ of Sec. 22, T10N, R. 66W. This ¼ section found a N+E only. Strikely runs thru it (NW to SE) and colony along slope N+S of streambed, which has flat bottom. I walked about to ascertain limits of colony and counted 76 burrows. Some doles filled so not open. Many open & possibly used by rabbits & C.L. No definite C.L. troche (Cold-35°F- & fair freeze). About 10 % ground bare, the rest variously covered with windblown snow. Many Lepus & apparent Sylvilagus tracks but no definite canawa troche.