Vol. VIII] 



VAN DENBURGH AND SLEVIN— GARTER-SNAKES 



191 



are 1+2—1+2 in eight, or 66% ; 1+2—1+3 in three, or 25% ; 

 and 1 + 1 — 1+2 in one, or 8%. The supralabials are 7 — 7 in 

 nine, or 75% ; 7 — 8 in two, or 17% ; and 8 — 8 in one, or 8%. 

 The infralabials are 10 — 10 in seven, or 58% ; 9 — 9 in four, or 

 33% ; and 9 — 10 in one, or 8%. The scale-rows are 19 — 19 — 

 17 in all. The gastrosteges vary in number from 157 to 168, 

 males having from 164 to 168, females from 157 to 166; the 

 average in five males is 165.4, in seven females, 161.1. The 

 urosteges vary from 74 to 87, males having from 84 to 87, 

 females from 74 to 79; the average in four males is 85.2, in 

 four females, 76. 



These variations are shown in full in the following table of 

 scale-counts. The series, of course, is too small to show the 

 real limits of variation. 



Scale counts in Thamnophis sirtalis parietalis 



Remarks. — The specimens at hand are insufficient to show 

 the western limits of the range of this subspecies and where and 

 how it meets, or merges with, or is replaced by, T. s. concinnus 

 and T. s. infernal is. The last named form ranges east at least 

 to the western edge of Nevada, while T. s. concinnus seems to 

 occur as far east as northern Idaho or, possibly, Montana. 

 Many more specimens are needed from southern Idaho, eastern 

 Oregon and all parts of Nevada, to throw light on these ques- 

 tions. 



