204 BULLETIN 5% UNITED STATES NATIONAL MUSEUM. 
incipient postorbital process ; upper surface of rostrum with distinct 
concavity on each side between lachrymal region and nares; other 
features of skull essentially as in Myotis , except for a general tendency 
toward broadening and shortening. Ear short, nearly as broad as 
long, the tragus short, straight, and bluntly rounded, its width more 
than half length of anterior margin. Interfemoral membrane furred 
on basal half above. 
Species examined. — Lasionycteris noctivagans (Le Conte). 
Remarks . — In its dention, Lasionycteris very closely resembles 
Myotis , differing only in the absence of the small, middle upper 
premolar. In the form of the skull and in the peculiar short, broad 
ears it shows greater specialization than some of the genera with more 
highly modified teeth. 
Genus PIPISTRELLUS Kaup. 
1829. Pipistrellus Kaup, Skizzirte Entwick.-Gesch. u. natiirl. Syst. d. europ. 
Tkierw., I, p. 98 ( pipistrellus ). 
1837. Pipistrellus Bonaparte, Icon, della Fauna Ital., I, fasc., XX. 
1838. Romicia Gray, Mag. Zool. and Bot., II, p. 495, February, 1838 ( calca - 
rata—kuhlii). 
1839. Vesper ago Keyserling and Blasius, Wiegmann’s Arckiv fiir Natur- 
gesckickte, 5ter Jahrg., I, p. 312 (part). 
1840. Romicius Blyth, Cuvier’s Animal Kingdom, p. 75. 
1856. Hypsugo Kolenati, Allgem. deutsch. naturliist, Zeitung, Dresden, neue 
Folge, II, p. 131 ( maurus and Jcraschenmikowii) . 
1856. Nannugo Kolenati, Allgem. deutsch. naturliist, Zeitung, Dresden, neue 
Folge, II, p. 131 ( nathusii , pipistrellus, and kiihlii). 
1864. Scotophilus H. Allen, Monogr. Bats N. Amer., p. 27, June, 1864 
(part). 
1871. Pipistrellus Dobson, Proc. Asiat. Soc. Bengal, p. 213. 
1878. Vesperugo Dobson, Catal. Cliiropt. Brit. Mus., p. 183 (part). 
1894. Vesperugo FI. Allen, Monogr. Bats N. Amer. (1893), p. 121, March 
14, 1894. 
1897. Pipistrellus Miller, Ann. and Mag. Nat. Hist., 6th ser., XX, p. 384, 
October, 1897. 
1897. Pipistrellus Miller, North Amer. Fauna, No. 13, p. 87, October 16, 
1897. 
Type-species. — V espertilio pipistrellus Schreber. 
Geographic distribution . — Entire mainland of Eastern Hemisphere 
to limits of tree growth, also Malay Archipelago, New Guinea, Solo- 
mon Islands, and northern Australia ; in America from northern 
United States (except in boreal zone) to southern Mexico. 
Number of forms . — About 40 species of Pipistrellus are now recog- 
nized. 
Characters. — Dental formula: 
-2 3. 1. - 2- 456 7 .2-2 1- 1 2-2 3-3 
1 2 3. 1. - 2 - 4 5 6 7 * 3 - 3’ c 1 - 2 - 2 ’ m 3 - 3 — rf4 ‘ 
