﻿88 



NORTH AMERICAN FAUNA. 



In America the genns is ropresented by three species, all of which 

 are strictly coii^'eueric with PlphtreJlus xniristreUm, Of the American 

 species P. suhflar us resembles P. xnpistreUus most closely, but is dis- 

 tinguishable at a glance by its much longer thumb. 



KEY TO AMERICAN FORMS OF PIPISTRELLTTS. 

 Tragus blnnt with tip bent forward : 



Forearm aboiit 31 mm. ; colors very pale liesperus (p. 88) 



Forearm about 28 mm. ; colors darker austraUs (p. 90) 



Tragus tapering and straight: 



Forearm 30 to 32 , rcrn'criicis (p. 93) 



Forearm 33 to 36— 



Color yellowish brown snyjiarus (p. 90) 



Color drab brown. ohscurns (p. 93^ 



PIPISTRELLUS HESPERUS (H.Allen). 

 1864. ScoiopMlus liesperus H. Allen, Monogr. N. Am. Bats, p. 43. 

 1878. Vesperugo liesperus Dobson, Catal. Chiroptera Brit. Museum, p. 228. 

 1886. Vesperugo merriami Dobson, Ann. & Mag. Nat. Hist., 5th ser., XVHI, p. 124. 

 1893. Vesperugo liesperus H. Allen, Monogr. Bats N. Am., p. 128. 



Type locality.— Fort Yuma, Cal. Type l^o. 5406, CJ. S. National Museum. 

 Geographic distribution. — Lower Austral zone in the Western United 

 States from western Texas to tlie Pacific Coast. Limits not knowu. 

 General characters. — Size very small (forearm about 26) 5 thumb short 



(about oue-eighth of forearm); ear shorter 



#and more bluntly rounded than in other 

 American members of the genns, reaching 

 barely to nostril when laid forward ; tragus 

 /f'f^W^ blunt aud distinctly bent forward at tip; 

 ^/l^S^H feet very small, abont half as long as tibia: 

 barely 1 mm. of tip of tail free from mem- 

 Av^^^ X? brane; color very pale. 

 ^ Uars.— The ears (fig. 20 h) are short, 

 FiG.20.-Ear of (a) Pimstreiius mh- jcacbing barely to nostril when laid for- 



flavus smdi (b) p. hesperxis iy.2). ^ , • -i t n • i • 



ward. The anterior border of auricle is 

 strongly convex from well developed basal notch to region about 

 middle, where it becomes straight and remains so almost to narrowly 

 rounded tip. Posterior border concave immediately below tip, then 

 strongly convex to basal notch. Basal lobe well developed, separated 

 from auricle by a deep notch and joining face at point below line of lips, 

 and slightly behind posterior corner of eye. The fur of the head extends 

 over dorsal surface of ear to slightly beyond the basal tb ird. Otherwise 

 the ear is naked except for a sprinkling of fine hairs on inner surface. 



Tragus less than half length of ear, broadest just below tip; ante- 

 rior border straight throughout greater part of its length, but strongly 

 concave immediately below tip; posterior border strongly convex from 

 tip almost to notch above well developed basal lobe. 



Membranes. — T\\e membranes are thin and delicate. Uropatagium 

 very sparsely furred at extreme base, otherwise naked except for a few 

 scattered liairs which are most numerous on the basal half. Wing 



