336 3. IGUANID.^ 



River near Pilot Knob, Hanlon's Ranch, Fort Yuma, Yuma 

 Indian Reservation), counties. 



In Lower California, it doubtless is restricted to the ex- 

 treme northeastern corner of the peninsula, where it has 

 been secured at Gardner's Laguna. 



It has been taken also on Tiburon Island, Sonora, Mex- 

 ico. 



Habits. — This large lizard is rarely seen on the open 

 desert, preferring the shelter of yuccas, mesquites, cotton- 

 woods and willows, about which it climbs with great agility. 

 It also is found in thickets, piles of rocks, earth banks, rail- 

 road culverts, old houses, on boulders, on the ground under 

 bushes, in caves, and occasionally even appears on bare hill- 

 sides. It is an adept climber and ascends to the tops of tall 

 bushes with great ease (Richardson). When approached 

 while on trees it dodges around to the opposite side of the 

 trunk or limb. If closely pressed it retreats to some place 

 of refuge such as a hole in the ground, a pile of rocks, or 

 the tuft of bayonet-like leaves at the end of a yucca stem 

 from whose remote depths no amount of poking or jarring 

 will induce it to leave (Grinnell & Grinnell). As it runs 

 from bush to bush Sceloporus magister lifts its tail above 

 the level of its body in much the same manner as Callisaurus 

 (Richardson). It sometimes is seen basking on rocks in 

 company with Sceloporus occidentalis biseriatus. 



Regarding its habits as observed near Tucson, Ruthven 

 writes: "It is very wary and rather difficult to secure as it 

 does not run about on the desert as do the Crotaphyti and 

 Cnemidophori but resides in the bushes. Individuals were 

 occasionally observed in Mesquite or Creosote bushes, and 

 more often beneath the Crucifixion thorn, but it evidently 

 prefers the tall branching Opuntias, especially the larger 

 ones. Here it may be seen very commonly on the trunks, 



