1918 | Grinnell: A Synopsis of the Bats of California 305 
Pipistrellus hesperus hesperus (H. Allen) 
Western Bat 
Scotophilus hesperus H. Allen (1864, pp. 43-44, figs. 38-40), part. Orig 
inal description; type locality, Fort Yuma, California [first locality 
mentioned in list of specimens]. 
Scotophilus hesperus, Cooper (1868, p. 5), part. Distribution. 
S[cotophilus]. hesperus, Cooper (in Cronise, 1868, p. 442). Nominal. 
Vespertilio (Vesperugo) hesperus, Coues and Yarrow (1875, pp. 94-95). 
Diagnosis; distribution. 
Vesperugo hesperus, True (1887, p. 515). Concerning the status of V. 
hesperus and of V. merriami. 
Vesperugo hesperus, Bryant (1891a, p. 358). Nominal. 
Vesperugo hesperus, H. Allen (1894, pp. 128-131, pls. 20-21). Deserip- 
tion; distribution. 
Pipistrellus hesperus, Miller (1897b, pp. 88-90, figs. 20-23), part. Descrip- 
tion; distribution. 
Pipistrellus hesperus, Elliot (1901, pp. 408-409, fig. 86), part. Diagnosis; 
distribution. 
Pipistrellus hesperus, Miller and Rehn (1901, p. 259). Type locality. 
Pipistrellus hesperus, Elliot (1904a, p. 320), part. Localities of capture 
in California. 
Pipistrellus hesperus, Elliot (1904b, pp. 582-583, figs. 86, 108), part. 
Diagnosis; distribution. 
Pipistrellus hesperus, Elliot (1905, pp. 480-481), part. Geographical dis- 
tribution. 
Pipistrellus hesperus, Stephens (1906, pp. 269-270), part. Description; 
distribution; habits. 
Pipistrellus hesperus, Elliot (1907, pp. 507-508), part. Localities of cap- 
ture in California. 
Pipistrellus hesperus; J. Grinnell (1908, pp. 159-160). Distribution and 
habits in the San Bernardino Mountains. 
Pipistrellus hesperus, Lyon and Osgood (1909, p. 274). Nature and loca- 
tion of type. 
Pipistrellus hesperus, Miller (1912, p. 60), part. General range. 
Pipistrellus hesperus hesperus, J. Grinnell (1913), p. 279), part. Range 
in California. 
Pipistrellus hesperus hesperus, J. Grinnell (1914, pp. 267-268). Occurrence 
on the Colorado River; habits; status of subspecies. 
Diagnosis—Size very small (total leneth, 62 to 80 millimeters; 
forearm, 26.6 to 30.7 millimeters); tragus blunt, with tip bent 
forward; general color of fur buffy gray above, whitish beneath; 
membranes, ears, and feet, blackish. 
Description: Head.—Muzzle short and broad, the greatest width 
of the rostrum equaling its length. Nostrils cireular and directed 
outward and downward; region between them shghtly concave. Eye 
small, inconspicuous and situated above and posterior to angle of 
mouth. A glandular swelling on each side of head between nostril 
and eye. Ear short, in an alcoholic specimen reaching only to a 
