TEIll) MZAKDS OF TLIK GENUS CNEMIDOPHOEUS 195 



sists on insects. Some ot" these, such as grasshoppers, are obtained 

 by stalking, just as a carnivorous mammal, such as the coyote stalks 

 a ground squirrel. Other prey, such as cutworms and beetle larvae, 

 are picked up from the surface of the ground about the bases of 

 plants.-' Woodbury (1928, p. 18) watched an individual "feeding 

 where insects had dropped on the ground at a light the night before. 

 It picked up numerous ants and termites and it even took one of 

 the termites from a large red ant but made no attempt to eat the 

 latter. It also picked up moths, bugs, and other types of insects that 

 were lying there dead or alive." If it were certain that some of the 

 insects selected were actually dead and showed no signs of movement, 

 due to wind or otherwise, when the lizard approached, the above 

 would be an especially interesting observation. Both live and dead 

 insects might have been on the ground, but the lizard may have 

 eaten only live ones. It has been the writer's general impression 

 that these lizards depend upon the movement of their prey for its 

 detection. (Burt, 1928, p. 64.) 



Apparenth' the first report of the analysis of the stomach contents 

 of tessellMibs was given by Stejneger (1893, p. 199), who wrote that 

 the food consists of "grasshoppers and other insects — no leaves or 

 flowers being found in the numerous stomachs examined." Ruthven 

 (1907, p. 563) examined the stomach contents of specimens from 

 Tucson, Ariz., and found the food to consist exclusively of spiders, 

 ants, beetles, grasshoppers, and other insects. The same conclusion 

 was reached by Euthven and Gaige (1915, p. 26) from a study of Ne- 

 vada specimens. Six Nevada specimens were taken on May 31 by 

 llichardson (1915, p. 425) and he found that they had their stom- 

 achs filled with "white larvae and j^ieces of gravel." Camp (1916, 

 p. 530) found a large grasshopper in the stomach of a Californian 

 specimen and in another a small beetle, a spider, and a quantity of 

 tiny yellow ants. 



A rather extensive account of the food of tessellatus was presented 

 by Pack (1923, pp. 85-90), who studied specimens in western Utah. 

 A total of 63 stomachs were examined and the results were presented 

 in tabular form. It was found that Lepidoptera, largely caterpil- 

 hirs, form 37.7 per cent of the food; grasshoppers, 14.4 per cent; 

 bcetk\s, 14.2 per cent, of which one-sixth are wire-worms ; miscellane- 

 ous insects, 14.27 per cent; arachnids, 8.2 per cent; and sand and bits 

 of wood. 2 23 per cent. " Hymenoptera, usually considered as one 

 of the most beneficial orders of insects, represents less than 1 per 

 cent of the total food. Without entering into a discussion of the 

 economic status of the various items of food, it is evident that a high 

 percentage of the total food consists of noxious insects. * * * It 

 is physically possible for this lizard to consume large quantities of 



