KEVISION OF THE KING SNAKES. 



81 



favoring topography. The present distinctness of the east and west 

 sections of hoylii, the availabihty of the southward route to the Great 

 Valley, and the improbability of a northward one argue for the greater 

 probability of the former route to northern and western California. 

 This suggests the hypothesis that hoylii was differentiated from 

 yumensis in southern Arizona and spread from there north to Utah, 

 Nevada, and eastern California, and that it was likewise differen- 

 tiated from yumensis in southern California and from here migrated 

 north throughout California west of the Sierras, and south to Cape 



Ventral 



254 



OCrt 









































246 

 242 

 238 

 234 













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 1 



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 1 



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 1 











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226 

 222 

 218 

 214 

 210 









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Tuc- Gra- Cen- Hack- Nee- Wild Inyo Over- Yu- San San Los Ava- Ft. Tu- Fres- San Shas- 

 son, ham tral berry, dies, Rose Mts.,ton, ma, Diego, Ja- An- Ion, Tejon, lare no, Fran- ta 

 Ariz. Mts., Ariz. Ariz, etc.. Spring, Calif. Nev. Calif. Calif, cinto, geles, Calif. Kern Co., Calif, cisco, Co., 



3 



Ariz. 11 1 Calif. Calif. 



1 4 



and 



18 



Calif. Calif. 



2 



Co., Calif. 



15 Calif. 



Calif. 





3 5 1 



Grand 



Ariz. 





11 13 





Calif. 3 



31 



7 



ar 



riES, AND NUMBERS OF 



Canyon, 



9 









3 









SPECIMENS. 



Ariz. 

















Fig. 17.— Diagram showing geographic variation in numbers of ventral plates in Lampropeltis getulus 



yumensis, and l. g. boylii. 



San Lucas. If there is any truth in this theory, there should be some 

 confirmation from a study and comparison of variations in scutellation 

 and pattern. 



Examination of figures 17 and 18, on which have been plotted the 

 extremes and averages of the ventral plates and the white annuli for 

 numerous localities, brings out the following interesting relations: 

 (1) All examples of hoylii from western and northern Arizona, Utah, 

 Nevada, and eastern California average much higher in number of 

 ventrals and almost distinctly higher in number of rings than exam- 



