Mayhew 1959 Journal 70. July 7 UCR campus, Riverside Co., Calif. 0730. We saw 6 Sceloporus occidentis shortly after reaching study area A, but could catch only one of them. The last animal was caught at 1030 when the air temp. (30") was only 29°C. We reached Darwin Hall again at 1110. July 9 4 mi. N.W. of Sunnymead, Riverside Co., Calif. This morning at 0610 Frank Aubrey & I left UCR to work the eastern slopes of Box Springs Mts. We caught the first animal we saw (Sceloporus occidentalis) at 0630. By 1055 we had captured 25 animals: Sceloporus occidentalis - 12 (9 ad. ♀, 3 ad. ♂) Sceloporus occidentis - 13 (2 ad. ♂, 3 ad. ♀, 6 imm. ♂, 2 imm. ♀) By this time the air temp (30") was 37.9°C, & at 1cm. it was 41.2°C. The campus was reached at 1120 after a trip of 24 miles. July 15 Lovejoy Buttes, 6½ mi. N. of Llano, Los Angeles Co., Calif. This morning at 0420 Frank Aubrey & I left UCR for this area of the Mojave Desert. We reached our former collecting areas just west of Phelan at 0530, but saw no animals in this area at the time we passed through. The first animal seen (young Sceloporus magister) was captured at 0600. The area by the road on the S.W. side of Lovejoy Buttes contains a rather large population of Sceloporus magister. In fact, we saw more members of this species