40. THAMNOPHIS 



Variation. — Two hundred and thirty-six specimens show 

 the following variations: The loreal is 1—1 in all. The 

 preocukrs are I— 1 in two hundred and thirty-six and 

 2—2 in one. The postoculars are 3—3 in two hundred and 

 fifteen or 92%; 3—4 in thirteen, or 5%; 2—3 in four, 

 or 2%; 4—4 in one, and 2—2 in one. The temporals are 

 ^+2 — 1+2 in two hundred and twenty-one, or 94%; 

 1 + 1— 1+2 in five, or 2%; 1+2—1+3 in four, or 2%,; 

 1 + 1—1 + 1 in four, or 2%; and 1+3—1+3 in one. The 

 supralabials are 7 — 7 in one hundred and eighty-three, or 

 77 %; 7—8 in forty-one, or 17%; and 8—8 in fourteen, 

 or 6%. The infralabials are 10—10 in one hundred and 

 sixty-nine, or 71%; 9—10 in forty-one, or 17%; 9—9 in 

 fifteen, or 6 % ; 8—9 in eight, or 3 % ; 8—1 in two, or 1 % ; 

 and 10 — 1 1 in two, or 1 %. The scale-rows are 19 — 17 — 17 

 in all specimens. The gastrosteges vary in number from 146 

 to 170, males having from 150 to 170, females from 146 to 

 167; the average in ninety-nine males is 164.3, in one hun- 

 dred and eighteen females, 156.4. The urosteges vary 

 from 66 to 95, males having from 70 to 95, females from 

 66 to 91; the average in eighty males is 84.2, in eighty- 

 eight females, 76.8. 



While a dark style of coloration with a tendency toward 

 narrow lines is characteristic of this subspecies, this type of 

 coloration is by no means constant. Specimens similar in 

 color to the type of pickeringii seem to be very rare even in 

 the far north. In general, the difference from T. sirtalis 

 farietalis and T. sirtalis infernalis lies in an increase in the 

 dark pigment, both dorsally and ventrally, rather than in 

 a marked narrowing of the lines or a reduction in the 

 amount of red in the coloration. 



Some specimens from Oregon are no darker than Cali- 

 fornian T. sirtalis infernalis^ and show red heads and often 

 much red on the body. Others are quite dark. Upon the 



