308 University of California Publications in Zoology (Vou. 17 
Chiroptera regards V. hesperus as identical with V. abramus, an Old 
World species. Later, Dobson (1886, p. 124) described a new species 
of North American Vesperugo under the name of V. merriami, basing 
his description on a single specimen sent him by C. H. Merriam. 
Dobson gives the type locality as Locust Grove, New York, the home 
of Dr. Merriam. Miller (1897b, p. 31) points out the error and 
states that the specimen really came from Red Bluff, Tehama County, 
California, and places the name merrianv in the synonymy of hes- 
perus. J. Grinnell (1913b, pp. 279-280) revives the name merriami 
and applies it to the race of hesperus occupying the Lower and Upper 
Sonoran zones in California west of the desert divides, thus restrict- 
ing the subspecific application of the name hesperus to the desert race. 
Distribution—Specimens available indicate that the range of 
Pipistrellus h. hesperus oceupies the Lower Sonoran zone chiefly east 
of the Pacific divides, comprising the Colorado and Mohave deserts, 
and extends from the Mexican line north at least to Coleville, Mono 
County (see map, text-fig. P). J. Grinnell (1913), p. 279) gives the 
range of this bat as extending west to Fort Tejon, Kern County; but 
the present writer finds upon examination of the specimens upon 
which this record was based that while Tejon specimens are not typical 
merrianu they bear a closer resemblance to that form than to Pipi- 
strellus h. hesperus. 
Specimens Examined.—The writer has examined 157 specimens 
of Pipistrellus hesperus hesperus, from the following localities in 
California: Imperial County: Colorado River near Pilot Knob, 18; 
Potholes, 4; four miles south of Potholes, 1; eight miles east of 
Picacho, 7; twenty miles above Picacho, 7; Thermal, 2; San Diego 
County: Carrizo Creek, 3; Santa Ysabel, 14 (U. S. Nat. Mus.) ; 
Jacumba, 2 (U. S. Nat. Mus.) ; Vallecito, 4; Dulzura, 6 (Amer. Mus. 
Nat. Hist.); Palmetto Spring, 3; Riverside County: Dos Palmos 
Spring, Santa Rosa Mountains, 5; Cabezon, 1; Banning, 1; Palm 
Springs, 4 (U.S. Biol. Surv., 3; Mus. Vert. Zool., 1) ; Palm Canon, 3; 
San Bernardino County: Borax Flat, 3 (U.S. Biol. Surv.) ; Needles, 
4 (U. S. Biol. Sury.) ; Colorado River opposite The Needles, 13; east 
base Turtle Mountains, 1; Barstow, 1; Victorville, 1; Warren’s 
Ranch, 1 (U.S. Biol. Surv.) ; Cushenbury Springs, 5; Kern County: 
west slope Walker Pass, 3; Weldon, 1; Onyx, 3; Fay Creek, 3; South 
Fork Kern River, 3 (U. S. Biol. Surv.) ; Kern River, 12 miles below 
Bodfish, 1; Inyo County: Lone Pine, 4 (Mus. Comp. Zool., 1; U.S. 
Biol. Surv., 3); Lone Pine Creek, 5; Independence, 1 (U. 8S. Biol. 
