SNAKES OF THE GENUS PITUOPHIS 



35 



Herrera (1889, p. 282) describes the structure and use of the vocal 

 apparatus, which are the same as in other forms of the genus. 



The following observations on the habitat of this form are given by 

 Herrera (1890, p. 338): "Se le encuentra mas comunmente cerca de 

 los depositos de agua sin corriente ; pero tambien suele hallarse en las 

 montanas cubiertas de plantas -herbdceas, aunque no se le ve jamds en 

 los bosques de conlferas, ne en los pedregales, 6 en el interior de los 

 lagos." 



Affinities. — The closest affinities of deppei are undoubtedly with 

 the two forms jani and lineaticollis, which may be included with it in 

 the deppei group. The former, although known from only two 



0.160 

 0.155 

 0.150 

 0.145 

 0.140 

 0.135 

 0.130 

 0.125 

 0.120 

 0.115 

 0.110 





Ccnifol 



Northc 

 Mexi: 



Tex 



Californid 



Southern 

 Mexico 



FiQURK 17.— Geographic variations in ratio of tail length to total length in Pituophis deppei deppei. 



locaHties, imdoubtedly has a range contiguous with that of deppei 

 (fig. 18). It has generally been considered identical with deppei, 

 and most of the characters of the two forms, while differing in some 

 cases on the average, overlap in range of variation. In pattern and 

 the number of spots they are distinct, however, and Cope's jani is 

 therefore retained as a subspecies of deppei. The ranges of deppei 

 and lineaticollis, on the other hand, overlap, and the two forms are 

 quite distinct in scale characters as well as pattern (fig. 19). The 

 tendencies exhibited in lineaticollis, and to a lesser extent in each 



