July, 1918 THE YOLLA BOLLY FOX SPARROW 139 



coast, details of the winter distribution of this subspecies are left for him to 

 touch upon in his coming paper. 



The principal differences between this new form and those nearest to it lie 

 both in coloration and in size and shape of the bill. It is impossible satisfac- 

 torily to express these differences in the name of the subspecies, so a minor 

 characteristic which can easily be expressed, has been featured in the designa- 

 tion. The tail averages a little shorter than in stephensi, and is shorter com- 

 pared with the wing than in the other forms approaching it, hence the name 

 brevicauda. A geographic designation would have been preferable, but the 

 most applicable one, that of the type locality, is too clumsy to latinize, though 

 possible to use unaltered for the vernacular name. The type, a breeding bird, 

 comes from the Yolla Bolly Mountains, which lie partly in Tehama County and 

 partly in southern Trinity County, California. The whole area of the breeding 

 range has not yet been determined. 



Passerella iliaca brevicauda, new subspecies 

 Yolla Bolly Fox Sparrow 



Type. — Female adult, no. 23924, Museum of Vertebrate Zoology ; y 2 mile 

 south of South Yolla Bolly Mountain, in Trinity County, California ; August 7. 

 1913 ; collected by A. C. Shelton and George Stone ; original number 385. 



Bange. — Breeding on the higher elevations of the Yolla Bolly Mountains, 

 which lie in southern Trinity and northwestern Tehama counties. In all prob- 

 ability this is the race reported as breeding on Mount Sanhedrin in the north- 

 ern part of Lake County. Winters south as far as southern California. 



Distinguishing characters. — Very large-billed race, closely approaching 

 Passerella iliaca stephensi, but head, including aural region, neck, back, and 

 spots on breast, decidedly brownish, the back being nearly fuscous brown, in- 

 stead of the mouse gray of stepliensi. The color of the back of brevicauda is 

 the exact match of that seen in many individuals of Pipilo c. crissalis from cen- 

 tral California. The size of brevicauda is about the same as stephi nsi, the only 

 important difference in measurements being that of the tail, which averages a 

 little shorter than that of stephensi, and which is also shorter, relatively, as 

 compared with the wing. Measurements of the type specimen are as follows 

 (measured by H. S. Swarth) : Wing 81.5; tail 80.5; culmen 14.8; depth of bill 

 14.0; width of bill 12.0; tarsus 25.0; hind toe and claw 18.0; middle toe and 

 claw 23.0. 



San Francisco, California, May 10, 1918. 



