13. PHRYNOSOMA 365 



Some species are oviparous, other ovoviviparous. The 

 food consists of insects such as beetles, flies, and especially 

 ants. These lizards are purely terrestrial, living on the 

 ground in the day and burying themselves before dark. 

 They usually resemble in color the soil upon which they 

 live, being blackish, reddish, gray, or nearly white, accord- 

 ing to their environment. Change in color is not rapid and 

 is said to require one or two days. 



In those species in which they are well-developed the 

 horns are of considerable protection to the species and pos- 

 sibly to the individual. When a horned-toad is handled 

 the head often is twisted about in such a way as to bring the 

 horns sharply in contact with the fingers. I have seen a 

 rattlesnake (Cro talus cerastes) with the horns of a Phryno- 

 soma it had partially swallowed protruding through the skin 

 of the neck of the snake. The same thing has been observed 

 in Crotalus oreganus. Another mode of defense, in at least 

 some species, is the curious squirting of blood which is 

 described under the headings P. b. blainvillii, P. b. frontale, 

 and P. cornutum. 



Although these animals usually live in very dry regions, 

 they drink greedily at times. They can exist for long 

 periods of time without either food or water. The colder 

 months are spent in hibernation under ground. Bryant 

 states: "A specimen of P. blamvillei blainvillei, plowed out 

 on December 15, 1909, was found to be in a state of hiber- 

 nation. The eyes were tightly closed and the lizard could 

 not be induced to open them 5 the muscles were set, the 

 animal often lying in a very awkward position. The breath- 

 ing was slow and erratic, intervals of several minutes inter- 

 vening between inspirations. The external temperature of 

 the body was about that of the air (15 degrees to 1 8 degrees 

 C.). Some ten minutes after placing the lizard in the sun, 



