REVISION OF THE KING SNAKES. 



29 



well distributed and indicate certain points which a fuller series may 

 confidently be expected to confirm. Thus the number of scale rows 

 is higher in the central and western portion of the range than in the 

 east. No specimen showed a lower maximum than 23 rows, but in 

 some of the specimens from central Texas this number was retained 

 for only a very brief space near the middle of the body, while in the 

 west it was present for a much greater distance, and some had 25 

 rows. The table of scale rows brings this out to some extent. 

 Approach to Tiolbrooki is shown also in the penial characters. That 

 form is characterized by having many minute spines below the large 

 ones, and this character is nearly as well developed in specimens of 

 splendida from San Diego, and Bexar County, Texas, as in typical 

 examples of Tiolbrooki; a specimen from Reeves County, in western 

 Texas, shows the minute spines present over nearly as great an area 

 as that occupied by the large ones, but they are only scarcely dis- 

 cernible, while specimens from Tucson, Arizona, show minute spines 

 present for only two or three millimeters below the large ones, thus 

 being close to yumensis in this respect. The ventrals and labials 

 seem to be much the same in one part of the range as in another. 



Table of scale rows in splendida. 



Fonnula. 



Arizona. 



New Mexico and 

 Western Texas. 



Central Texas. 



Totals. 



Male. 



Female. 



Male. 



Female. 



Male. 



Female. 



Male. 



Female. 



23-25-23-21-19 



2 

 1 

 1 







1 

 3 







2 



4 

 4 



1 

 5 

 5 



23-21-19 



1 

 1 



2 

 2 



1 

 1 



I 



21-23-21-19 



Total 



4 



2 



4 



4 



2 



5 



10 



11 





The most noticeable geographic variation occurs in the color pat- 

 tern, the full significance of which will be brought out in the discus- 

 sion of the evolution of the color pattern in the getulus group. Briefly 

 it is as follows: Westward from the central portion of the range the 

 number of dorsal cross bands is decreased perceptibly; they become 

 broader, the dorsal black areas become wider, and, on the sides, 

 opposite each dorsal white band, there is a fading out of the white 

 spots, tending to produce a series of lateral dark areas in alternation 

 with the dorsal series. Eastward from this central region, the white 

 centers of the cross bands tend to lose their symmetrical orientation 

 parallel to the long axes of the scales; the number of bands decreases 

 somewhat; the dorsal dark areas widen very slightly; there is a dis- 

 tinct tendency for the development of a lateral alterDating series of 

 dark areas, as in the western forms, sometimes also a second and 



