728 13. COLUBRIDM 



7%; and 14 14 in one, or 4%. The scale-rows are 33 in 

 eleven, or 39%; 31 in eleven, or 39% ; 35 in three, or 1 1 % ; 

 29 in two, or 7% ; and 37 in one, or 4% ; the average is 32.3 

 rows. The gastrosteges vary in number from 223 to 263, 

 males having from 224 to 252, females from 223 to 263; 

 the average in twelve males is 234, in sixteen females, 239. 

 The urosteges vary from 50 to 72, males having from 58 to 

 72, females from 50 to 67; the average in twelve males is 

 64, i*> ^ifteen females, 59. 



The dark blotches between head and anus in 28 speci- 

 mens vary from 46 to 66, the average being 55. On the 

 tail they vary from 12 to 21, and average 15.4. 



Distribution. In California this subspecies occupies the 

 Colorado and Mohave deserts and the southern end of the 

 San Joaquin Valley. It ranges north and east over most of 

 Nevada. 



From Nevada I have examined specimens of this sub- 

 species from Humboldt (Thousand Creek Flat, Virgin Val- 

 ley, Big Creek Pine Forest Mountains), Washoe (Pyramid 

 Lake, Nixon), Ormsby (Carson), Lander (Austin), Elko 

 (Carlin), Nye (Peavine Creek, Toiyabe Mountains, Round 

 Mountain at 6,300 feet), and Esmeralda (Palmetto Moun- 

 tains), counties. 



Californian specimens examined have been collected in 

 Imperial (Silsbee), Riverside (Mecca), San Bernardino 

 (Victorville, Hesperia), Mono (Benton), Kern (Walker 

 Pass, Tehachapi Mountains, Isabella, Delano, Bakersfield, 

 Button willow), and San Luis Obispo (Simmler, Poso, Palo 

 Prieto, Shandon) counties. 



Remarks. Some of the specimens from the San Joa- 

 quin Valley and eastern San Luis Obispo county approach 

 more or less closely to the characters of P. catenifer heer- 



