222 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
canines well developed, not peculiar in form; anterior upper pre- 
molar minute, occupying the inner angle between canine and large 
premolar ; other cheek teeth strictly normal ; m 1 and m 2 without 
hypocone, m 3 much reduced, its crown area less than one-third that 
of m 1 , the protocone, paracone, parastyle, and first commissure well 
developed, the mesostyle and second commissure obsolete, though not 
absent; lower molars with, all the cusps well developed, m 3 with dis- 
tinct entoconid. Skull short and broad, the brain case high and 
rounded, the rostrum sloping away rapidly in front so that its 
upper surface is nearly in line with that of brain case; nares and 
palatal emargination wide and shallow, the width of the emargination 
distinctly greater than its depth; palate sloping upward anteriorly, 
and floor of brain case rising posteriorly so that the two surfaces are 
set at noticeably different angles ; audital bullse well developed but 
not large, their diameter about equal to width of space between; 
basisphenoicl pits narrow and elongate, but distinct; zygomata slen- 
der, not expanded at middle or elsewhere. Ear short, rounded. 
Wing with fifth finger much shorter than third, the third metacarpal 
usually exceeding fifth by at least length of thumb, though by dis- 
tinctly less than length of thumb in L. borealis. Interfemoral mem- 
brane very large, most of its upper surface furred. Mammae, 4.® 
Species examined. — Lasiurus borealis (Muller) and the related 
forms, also L. cinereus (Beauvois) and L. semota (H. Allen). 
Remarks. — This genus is well characterized by the short, deep 
skull, the graduated metacarpals, and the furred interfemoral mem- 
brane. The only genus that it is likely to be confused with is the 
closely related Dasypterus , from which it is distinguished by the pres- 
ence of the small upper premolar {pm 2 ). 
Genus DASYPTERUS Peters. 
1864. Lasiurus H. Allen, Monogr. Bats N. Amer., p. 25 (part). 
1871. Dasypterus Peters, Monatsber, k. preuss. Akad. Wissensch., Berlin, 
1870, p. 912 (subgenus of Atalapha). 
1878. Dasypterus Dobson, Catal. Cbiropt. Brit. Mus., p. 274 (subgenus of 
Atalapha). 
1894. Dasypterus PI. Allen, Monogr. Bats N. Amer. (1893), p. 137, March 
14, 1894. (Genus.) 
1897. Dasypterus Miller, North American Fauna, No. 13, p. 115, October 
16, 1897. 
Type-species. — Lasiurus intermedius H. Allen. 
Geographic distribution. — America, from the southern border of 
the United States (including Florida and the Gulf coast) southward; 
not yet recorded from the West Indies. 
« For notes on the mammae and the unusual number of young in the Lasiurine 
bats, see Lyon, Proc. U. S. National Museum, XXYI, pp. 425-426, Janhary 26, 
1903, and Ward, Science, n. s., XXII, p. 20, July 7, 1905. 
