BATRACHIANS OF THE VICINITY OF NEW YORK 195 



others to a bright tint of green. While the animal was in the 

 green phase, the pattern on the back could not be discerned. 



The toes are provided with well-developed adhesive disks, 

 or "suckers," which are particularly distinct on the fore feet. 

 The skin of the abdomen is coarse and granulated; that of the 

 back is smooth. 



Male specimens of this species may be distinguished from 

 the females by the loose, dark skin on the throat. This loose 

 skin constitutes the vocal sac, an organ capable of great ex- 



FIQ. 20. PICKERING'S TREE TOAD 

 From specimen in New York Zoological Park 



pansion while the animal is uttering its shrill mating call. Length 

 of body, \\ inches; total length, hind limbs outstretched, 2\ 

 inches. 



Range: The entire eastern and central portions of the United 

 States, abundant. 



Local Distribution: Common, but not easily seen. 



Only three representatives of the genus Hyla are found in this 

 vicinity.^ The species are easily distinguished from one another 

 by their characteristic color-patterns, and from other tailless 

 batrachians by their peculiar feet and the disks on the toes. 



' One species, the Hyla andcrsoni. is of doubtful occurrence, although it is 

 included in this Leaflet. 



[4.] 



