32 



BULLETIN 17 5, UNITED STATES NATIONAL MUSEUM 



they range from 27-27-21 to 29-31-22, the formula tending to be 

 higher in females than in males, as in other forms of the genus. Ven- 

 trals vary from 211 to 225 (average 220.3) in males and from 215 to 

 233 (average 223.3) in females, while caudals average 62.6 in males 

 and 60.1 in females. The variation in proportionate tail length ranges 

 from 0.130 to 0.157 (average 0.145) in males and from 0.127 to 0.156 

 (average 0.136) in females. The average number of supralabials, in- 



Southern 

 Meiico 



CcntMl Nothc 



Figure 14.— Geographic variation in number of caudals in Pituophis deppei deppei. 



fralabials, and postoculars is slightly higher in each case in males than 

 in females, as in lineaticollis and sayi, while the reverse is true in most 

 of the other forms of the genus. Contrary to expectation, in con- 

 sideration of the proportionately longer body of females, as indicated 

 by the higher number of ventrals, the number of body spots, as well as 

 of tail spots, is higher in males. The total number of spots on body 

 and taU averages 50.4 in males and 47.8 in females. 



