REVISION OF THE KING SNAKES. 



85 



bridged in central Arizona; (2) the head pattern shows no develop- 

 ment not initiated in yumensis; (3) the change in coloration of the 

 white rings is effected in the vicinity of the Florence River, the 

 approximate boundary between the ranges of the two forms. 



The western section of hoylii approaches yumensis in southern 

 California, and from here are developed new, although sometimes 



Hg. 20.— Map showing locality records for Lampbopeliis getulus bovlii. 



minor and local changes, northward and southward. Comparison 

 of variations and consideration of topography make it fairly evident 

 that the Great Valley of California has been populated from the 

 south and not from the east or from the north. 



The relations of hoylii to conjuncta and to calif omiae are discussed 

 under those forms. 



