150 ECONOMIC ZOOLOGY 



fact all of our lizards are entirely harmless with the exception of the 

 beaded lizards, of Mexico and the extreme southwestern part of the 

 United States, to be described below. 



In studying the lizards of Pennsylvania, Surface found no vegetable 

 food in any of the stomachs examined. It is probable that the food 

 of our common lizards, Fig. 100, consists largely of insects, and that 

 they do a great amount of good in destroying these pests and hence 

 should be protected everywhere. Some species seem especially fond of 

 grasshoppers. 



The Beaded Lizards, Heloderma suspectum and H. horridum. As 

 noted above these lizards are the only ones on this continent, so far as is 

 known, that are venomous. Southern Arizona and New Mexico is 

 the habitat of the first species; western Mexico and Central America of 

 the second. The former, known as the Gila (pronounced Heela) 

 Monster, may be seen in many of our zoological parks, and reaches a 

 length of 1 8 to 24 inches. While tame and good-natured in captivity, 

 it is said to be of a very different disposition in its native environment, 

 and strange tales are told of its ferocity and of its tenacity of grip. 

 Its poison fangs are in its lower jaw and it is commonly said that it 

 turns upon its back, in biting, to cause the poison to flow into the wound; 

 whether or not this be true the writer is not able to say. 



There is considerable difference of opinion as the effect of the bite 

 of the Gila Monster, some claiming it to be very deadly to human beings, 

 others holding the opinion that it has but little effect upon man. Dit- 

 mars is of the opinion that the beaded lizards are "dangerously poi- 

 sonous to man." Being easily recognized by the bead-like, brightly 

 colored skin and club-shaped tail there is no reason for confusing these 

 with the harmless lizards, and their restricted range makes them of no 

 importance to the vast majority of our people. Even in their native 

 range they are so scarce that the writer wandered many miles over the 

 Arizona desert searching in vain for a single specimen. 



It is probably safe to say, then, that all of our lizards, with the ex- 

 ception of the two species just described, are not only entirely harmless 

 to man and to vegetation but that they are highly useful as insect 

 destroyers. 



In many tropical countries both the lizards themselves and their 

 eggs are largely used as food. It is the huge Iguanas, Fig. 101, reaching 

 a length of six or more feet, that are chiefly used in this way. The flesh is 



