E.V. Miller 1940 Microtus Mexicanus May 5 10,800± ft. La Providencia, NW slope Popocatepetl, Mexico. Took 3, 1♂, 1♀, (other?) of this species along a small creek. Bunch grass, a little brush and fir trees were the dominant plants. The soil was fine, and dark in color. May 8 12,000± ft. NW slope Nevada de Toluca, Mexico. Took 3♀, 2♂(?) this species in traps set in thick bunch grass under a thin stand of pines 75-100 ft. high, along a small creek.