40. THAMNOPHIS 811 
Variation.—Twenty-one specimens from Arizona have 
loreals 1—1 in all. The preoculars are 1—1 in all, but 
one, which has 1—2. The postoculars are 3—3 in all but 
three which have 3—4. The temporals are 1+2—1+2 in 
fourteen, 1+2—-1+3 in three, 1+3—1+3 in three, and 
2+3—2+3 in one. The supralabials are 8—8 in twenty, 
and 8—9 in one. The infralabials are 10—10 in seven- 
teen, 11—11 in two, 10—11 in one, and 9—10 in one. 
The scale-rows are 19—19—17 in all but one, which has 
21—19—17. The gastrosteges vary in number from 164 
to 175, males having from 166 to 175, females from 164 to 
171; the average in thirteen males is 170.6, in seven 
females, 168. The urosteges vary from 77 to 97, males 
having from 85 to 97, females from 77 to 88; the average 
in twelve males is 91.7, in six females, 83.5. 
Distribution—This snake occurs in the United States 
in Arizona, New Mexico and western Texas. Thence it 
ranges south through Mexico to Guatemala. In Arizona 
it has been found in the plateau region and about the foot- 
hills of various mountain groups. Ruthven has recorded it 
from Fort Apache, Fort Huachuca, White River Canyon, 
Sabino Canyon, and Fort Whipple, Arizona. We have 
examined specimens from Maricopa (Cave Creek), Coco- 
nino (Oak Creek), Pima (Catalina Mountains, 18 miles 
north from Tucson, Sabino Canyon, Catalina Mountains, 
Sawmill Canyon, Santa Rita Mountains), and Santa Cruz 
(canyon between Madera and Agua Caliente canyons, Cot- 
tonwood Canyon, Agua Caliente Canyon, Gardner Canyon, 
and Stetson’s Dam, all in the Santa Rita Mountains) 
counties, Arizona. Dr. Stone has recorded this species from 
Sycamore Canyon, Baboquivari Mountains, Arizona; and 
Dr. Stejneger from Fort Huachuca, Arizona. 
