72 



tive at lower air and body temperatures. Termites are the major food 

 for southern populations, beetles and grasshoppers for northern popula- 

 tions. Seasonal food trends are evident; insect larvae are an impor- 

 tant early food source for all populations. Lizards eat a wide variety 

 of food types where primary productivity is low and specialize more 

 where it is high. Greater food competition with other lizard species 

 in the south as well as the lack of termites in the Great Basin desert 

 may account for some of these differences, in the opinion of the author 

 of this review. Foraging behavior is described. Southern populations 

 are subject to greater predation. Fat body size is not correlated with 

 latitude but is inversely correlated with long-term average annual pre- 

 cipitation. It is suggested that lizards from less productive areas 

 must allow themselves a greater margin of safety due to more probable 

 occurrance of drought. Northern lizards breed only once a year but lay 

 significantly larger clutches than southern lizards, which lay at least 

 2 clutches annually. Clutch size appears to be flexible in response to 

 resource availability. There is a significant correlation between mean 

 clutch size and deviation of the short-term (last 5 years) mean preci- 

 pitation from long-term mean precipitation. Ecological challenges for 

 northern lizards are primarily physical and largely climatic, whereas 

 biotic interactions assume relatively greater importance for southern 

 lizards. 



188. Pietruszka, R. D. 1981a. An evaluation of stomach flushing for 

 desert lizard diet analysis. SOUTHWESTERN NATURALIST 26: 101-105. 



The latest on the technique is reported, with Cnemidophorus 

 tigris from Nevada one of 5 species used. 



189. — . 19Slb. Use of scutellation for distinguishing sexes in bi- 

 sexual species of Cnemidophorus . HERPETOLOGICA 37(^): 2^^-2f9. 



Males of several species of Cnemidophorus (including gularis , 

 inornatus , sexlineatus and tigris from New Mexico) possess a row of 

 slightly to distinctly enlarged scales on either side of the ventral 

 surface of the tail, distally separated from the vent by 2-4 granular 

 scales, called the postanal ridge. Immediately posterior to each ridge 

 is a distinctly shaped enlarged scale, the postanal plate. Females 

 possess the former but not the latter. The utility for use of this 

 character in field studies in view of the lack of other reliable sex 

 determining mechanisms is discussed, along with variation of the trait. 

 Small series of several parthenogenetic species demonstrate only the 

 female characteristic. 



190. Presch, W. 197ita. Evolutionary relationships and biogeography 

 of the macroteiid lizards (Family Teiidae, Subfamily Teiinae). BULL- 



