SNAKES OF THE GENUS PITUOPHIS 



129 



45.8 in males, 46.3 in females; tail spots average 13.9 in males, 12.6 

 in females; proportionate tail length varies from 0.121 to 0.150 (aver- 

 age 0.136) in males, from 0.111 to 0.144 (average 0.127) in females. 



Range. — This form is found as far south as Batapilas, Chihuahua, 

 Mexico, and north to Pagosa, Colo. It ranges throughout Arizona, 

 east in New Mexico to Otero and Guadalupe Counties, west in 



15 48 19 28 10 



Region No. 1 2 3 4 5 



Figure 61.— Geographic variation in ratio of tail length to total 

 length in Piluophis sayi affinis. 



86 

 84 



82 



80 



78 

 76 

 74 

 72 

 70 

 68 

 66 

 64 

 62 

 60 

 58 

 56 

 54 

 52 

 50 

 48 

 46 

 44 

 42 



Region 

 No. 1 



FiGXJKE 62. — Geographic variation in total 

 number of dorsal spots in Pituophis sayi affinis. 



California to Silsbee, Imperial County, and south in Lower California 

 to the Colorado desert. 



Specimens have been examined from the following localities: 



Mexico: Chihuahua, Madera, Pacheco, Chihuahua, Casas Grandes, Ahumada, 

 near Batapilas; Lower California, Colorado Desert, 23 miles north of El 

 Mayor; Sonar a. 



New Mexico: Bernalillo County, Isleta; Dona Ana County, Las Cruces; Grant 

 County, Santa Rita del Cobre, Redrock, Hachita; Guadalupe County, Anton 

 Chico; Lincoln County, Jicarilla Mountains; McKinley County, Wingate, 



