312 University of California Publications in Zoology [Vou.17 
length of cranium, 11.6 (11.38-11.8); ten females: total length, 73.6 
(67.0-78.0) ; tail vertebrae, 29.2 (26.0-34.0) ; tibia, 11.4 (11.1-11.7) ; 
foot, 5.6 (5.0-6.0); forearm, 29.6 (28.0-30.8); greatest length of 
eranium, 12.0 (11.9-12.2). 
Synonymy and History—The synonymy and history of this bat 
is ineluded with that of P. h. hesperus on page 306. In his original 
description of Pipistrellus hespcrus, H. Allen (1864, pp. 43-44) does 
not designate a type, but lists three specimens, the first being from 
Fort Yuma and the two remaining from Poso Creek (Kern County). 
Miller (18970, p. 88) designates the Fort Yuma specimen (no. 5406 
U. S. Nation. Mus.) as the type of hesperus. I have examined the 
two skins (nos. 5509 and 5570 U. S. Nation. Mus.) from Poso Creek 
and find them to be Pipistrellus hesperus merriami, as would be ex- 
pected from the geographic position of this locality. 
Distribution—Specimens examined indicate the range of this bat 
as lying within the Upper Sonoran and Transition zones altogether 
west of the desert divides, from the Mexican line northwest through 
the San Diegan district and through the San Joaquin and Sacramento 
valleys, east of the humid coast belt and west of the Sierra Nevada, to 
Butte and Tehama counties (see map, text-fig. P). Specimens from 
Witch Creek (or Santa Ysabel), San Diego County, are allocated with 
difficulty, some appearing to be nearest hesperus and others nearest 
merriamt. . 
Specimens Examined.—The writer has examined 46 specimens 
of Pipistrellus h. merriami, from the following localities in California : 
San Diego County: Twin Oaks, 2 (U. S. Biol. Surv.) ; Escondido, 1; 
Witch Creek, 4 (San Diego Soe. Nat. Hist., 1; U.S. Nation. Mus., 3) ; 
Riverside County: San Jacinto Mountains, 2 (U. 8. Nation. Mus.) ; 
San Jacinto Lake, 5 (U. S. Nation. Mus.); Los Angeles County: 
Pasadena, 1; Rubio Wash, near Pasadena, 3; San Francisquito Canon, 
1; San Gabriel Cafion, 2 (U. S. Biol. Surv.) ; Kern County: Grape- 
vine Canon, near Fort Tejon, 3; San Emigdio, 1 (U. 8. Biol. Surv.) ; 
Poso Creek, 2 (U. S. Nation. Mus.); San Luis Obispo County: 
Cuyama Valley, 1; Mariposa County: El Portal, 1; Pleasant Valley, 
2; Yosemite Valley, 3; Madera County: Raymond, 3; Solano County: 
three miles west of Vacaville, 1; Yolo County: Rumsey, 3; Eldorado 
County: Limekiln, 2; Fyffe, 1; Sutter County: Butte Slough, 1; Men- 
docino County: Mt. Sanhedrin, 1 (Acad. Nat. Sei. Phila.). 
Natural History—tThe time of breeding and number of young is 
indicated by the following data, taken from specimens in the Museum 
of Vertebrate Zoology : female, no. 18497, taken near Vacaville, Solano 
