186 CALIFORNIA ACADEMY OF SCIENCES. 



(Mill Valley, Camp Taylor), Sonoma (Healdsburg), 

 Mariposa (Yosemite Valley), El Dorado (5,000 feet), 

 Placer (Red Point), Lassen (Honey Lake), and Shasta 

 (McCloud River) Counties, California. It crosses Ore- 

 gon (Klamath Lake, Summer Lake, Warner's Valley, 

 Willamette Valley, Dalles) to Washington (Ft. Steila- 

 coom, Puget Sound) and Idaho (Atlanta, mouth of Bru- 

 neau River, Big Butte). 



Habits. Like other members of its genus, the West- 

 ern Yellow-bellied Racer is a skillful climber and often 

 runs through the tops of the bushes at almost as great 

 a speed as when upon the ground. It is frequently 

 found, however, in open country or in fields of growing 

 grain. 



59. Bascanion flagellum frenatum Stejneger. WESTERN 

 WHIP SNAKE. 



Bascanium flagelliforme testaceum, YARROW, Bull., U. S. Nat. Mus., 



24, 1882, p. 112 (part). 

 Bascanium testaceum, COPE, Proc. Ac. Nat. Sci. Phila., 1883, pp. 



29, 32. 

 Bascanium flagelliforme, COPE, Proc. U. S. Nat. Mus., XIV, 1891 



(1892), p. 625 (part). 

 Bascanion flagellum frenatum, STEJNEGER, N. A. Fauna, No. 7, 



1893, p. 208 (type locality Mountain Spring 1 , Colorado 



Desert, San Diego County, Calif. ) 



Description. Head rather long, with flattened top, and 

 narrow, rounded snout. Rostral plate large, high, hol- 

 lowed below, and bounded behind by internasal, ante- 

 rior nasal, and first labial plates. Plates on top of head, 

 a pair of internasals, a pair of prefrontals, supraocular 

 and part of upper preocular of each side, long frontal, 

 and pair of large parietals. Anterior and posterior 

 nasals distinct. Loreal well developed. Preoculars 

 normally two, but sometimes united. Postoculars two, 

 upper a little larger. Temporals normally two followed 



