Diagnosis.—Size medium for the species; total length, 71.8(66-74); tibia, 12.0(10.7-13.5); forearm, 29.4(27.8-31.8); greatest length of skull, 11.9(11.5-12.3); breadth of braincase, 6.3(6.1-6.4). Color between Drab Gray and Smoke Gray, dorsally; between Smoke Gray and Pale Smoke Gray, ventrally (after Hatfield, Jour. Mamm., 17:257, 1936).
Pipistrellus hesperus merriami (Dobson)
Vesperugo merriami Dobson, Ann. and Mag. Nat. Hist., 18(ser. 5): 124, August, 1896.
Pipistrellus hesperus merriami Grinnell, Proc. California Acad. Sci., 3(ser. 4):279, August 28, 1913.
Type locality.—Red Bluff, Tehama County, California.
Range.—California west of the Sierra Nevada; the Sacramento Valley, the San Joaquin Valley, and the Coast Range from San Francisco Bay south to San Diego County. Marginal occurrences (after Hatfield, Jour. Mamm., 17:260, 1936, unless otherwise noted) are: California: Dales on Paines Creek; Fyffe; Yosemite Valley; Shaver Ranger Station; Springville; Fort Tejon; Painted Gorge (P. H. Krutzsch, MS); Carrizo Creek; thence northward up the coast probably to San Francisco Bay; in the Sacramento Valley west to Rumsey.
Diagnosis.—Size medium for the species; total length, 71.3(66-78); tibia, 11.2(10.6-11.7); forearm, 28.9(27.5-30.8); greatest length of skull, 11.8(11.3-12.2); breadth of braincase, 6.4(6.0-6.6). Color Buffy Brown to Army Brown, dorsally; Wood Brown to Buffy Brown, ventrally (after Hatfield, op. cit.: 258, 260).
Pipistrellus hesperus australis Miller