R. Zweifel 1953 Cnemidophorus tigris 4.7 mi. N Ciudad Obregon, Sonora, Mexico 2567-2572 RZ July 19, 1953 Collected in the late afternoon (5:30 - 6:00 PM) in partly cleared area of very fine soil by the roadside. Various thorny bushes and small trees do not give continuous cover; cover estimated at 40% down to much less. The largest individual, SV- mm), has a black gular area and black ventre. Two others show black chine but less extensive black on the ventral surface. Three others are white beneath. One of the dark- ventered lizards was shot while courting a white- ventered individual. The smallest lizard, SV- mm), has six pale yellow lines on a dark background with no spots in the lateral or dorso-lateral fields. The central line is continuous on the neck but represented only by a series of dots back to the pelvic region. In the larger individuals, the central stripe tends to be continuous back to the base of the tail. Only the faintest suggestion of spotting is present in the lateral field. The whole coloring is much browner, the stripes being less distinct.