REVISION OF THE KING SNAKES. 169 



Affinities. — Very few specimens are available from the southern 

 portion of the range, but the indication is that no constant differences 

 will be found to separate gentilis from annulata. Their close affinity 

 is indicated in every characteristic. Annulata becomes gentilis when 

 the yellowish annuli widen on the sides and restrict the black on the 

 belly to an area no greater than that of the yellow, and when the black 

 snout becomes lightened with reddish. Intergradation certainly takes 

 place with amnaura and with sijspila where their respective ranges 

 meet its own. The relationship held to exist between these forms 

 and discussed at greater length in the summary of this group may be 

 expressed in the following diagram : 



gentilis syspila 



(Utah, Col.) / 



gentilis > amaura 



(Texas) 



T 

 annulata 



FiQ. 50.— Diagram showing mTERBELATioNsmps between Lampropeltis trungulum annulata 



L. T. gentilis, L. T, AM\tJRA, AND L. T, SYSPILA. 



