Journal Hefner, H.S. 1977 10 km. S., 16 km. W Toluca, 3000 m., México, México. 3 August (cont) at a depth of about 300 mm below the surface. It appeared to have only one entrance. In another burrow system I uncovered a cache (roots, etc.) of bulbs and such, most of which were now sprouted. The bulbs were about 2 cm. in diameter. The cache, itself, was in a sealed-off chamber about 100 mm in diameter and 80 mm. below the surface. We set the skins out to dry in the warm afternoon sun. At 1430 we pulled traps and departed the locality: Results: 19 Thomomys umbrinus We drove to Toluca, through the city, then NE on Hwy 130 toward Naucalpan, a suburb of México City. We were in need of liquid Nitrogen for out tissue and blood samples and we were told we could get some in Naucalpan. The road to Naucalpan climbed over the mountains separating Valle de Toluca from Valle de México. The road was narrow, rough and crowded. 1630 we finally arrived in the dirty, industrial city of Naucalpan. After an hour of hunting for the "Argon Gas Co." we finally located it in an obscure section of town. The local people were of little