Good C. brunneicopillus habitat stops just south of San Juan del Res - road then climbs through deciduous broad-leaved forest mixed with some pines which are similar to the yellow pine. Road continues along the edge of a valley till A cambay, Pathe where the whole valley is farmed, although there are some good patches of tuna cactus (good-sized plants) on the hill sides. Some slopes here are covered with pine, others with deciduous trees and pines. 2 mi. N of Atlacomulco there is a slope of tuna cactus on the left hand side of the road and beyond this point there are other slopes of tuna cactus remaining. At a settlement somewhere near Ixtlahuaca I stopped and questioned some natives about the occurrence of C. brunneicopillus. After that I showed a specimen to several natives but all said it did not occur here. One person knew the species and told me that they occur in the lower country to the north (= Queretaro). Probably Acambay is near southern limit of distribution of C. brunneicopillus although the cactus formation occurs further south in the high Toluca Valley,