NOTES ON THE OECOLOGY AND LIFE-HISTORY OF THE 

 TEXAS HORNED LIZARD, PHRYNOSOMA C0RNUTU3I 



Y By J. P. GiVLER 



It was my privilege during two summers spent in a study of Phry- 

 nosoma in southern Kansas* to observe and record many facts of 

 bionomic interest in relation to this well-known creature. The region 

 named also made available for study directly in the field, in comparison 

 with Phrynosoma, representatives of several other genera and four 

 families of Lacertilia. In the laboratory comparative studies were 

 made of general morphology, reproductive organs, eggs and embryos. 



The following account is intended to serve as a record of some of 

 these observations and to present in one view a brief account of the 

 bionomics of reproduction of this reptile. 



EMERGENCE FROM HIBERNATION 



In southern Kansas the Texas Horned Lizard comes forth about 

 May first. When the ''toads" first appear in the spring they are 

 thin and emaciated, sluggish, and very dark in color, ^t first the 

 males greatly preponderate over the females in numbers, being in the 

 ratio of three or four males to one female. Later the females emerge 

 in greater numbers, tending to equalize the sexes. 



From the beginning of their life, ex-hiberna, their activity is de- 

 pendent, principally, upon the sun's light and heat. In the morning 

 they are very sluggish and, when touched, will scarcely move. Later, 

 as they become warmed by the sun, they run about, seek ants and 

 other insects as food and move with a sudden characteristic impetu- 

 osity. They are warned at the slightest sound or movement and fre- 

 quently stop to raise and lower themselves by their front legs, an 

 amusing habit to be appreciated fully only by those who have seen it. 



During these early days of spring the Phrynosomas mate freely, 

 the preponderance of males at the outstart, as well as the gradual 

 emergence of the females, insuring the insemination of all of the latter. 

 This is attested to by the fact that, among hundreds of eggs studied, 

 only one was found infertile. 



SEXUAL DIMORPHISM 



Winton ('14) states for this species observed farther south that, 

 especially in early spring, the yellow cervical crescents are much 



Winfield and vicinity. 



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