ALLEN — BATS FROM MOUNT WHITNEY 
5 
the tops of the pines surrounding the camp. The flight is rather slow 
and weak as compared with that of M. lucifugus. In addition to its 
longer tibia and smaller hind foot, this species is easily distinguished 
from the lucifugus group by its well-keeled calcar. 
Eptesicus fuscus (Beauvois) 
LARGE BROWN BAT 
At our 11,000-foot camp, one or two large brown bats were seen 
nearly every evening, distinguished by their size and relatively slow 
steady flight. Of those shot only one, an adult male, was retrieved. 
It is quite identical in color with two females shot at Lone Pine, at the 
base of the mountain, and is not to be distinguished from eastern 
skins. Thus the wide geographical range of the species corresponds 
with its altitudinal distribution. 
General remarks. — It is probably significant that all five specimens 
obtained at 11,000 feet on Mount Whitney, representing four species 
of bats, are males. The presence of Myotis longicrus interior, M. 
yumanensis sociahilis, and Eptesicus fuscus above the Transition or 
Lower Canadian zones appears to be unrecorded in California, yet all 
three were collected in what would be considered for ground-living 
mammals, a boreal (Hudsonian) zone. This wide range in altitudinal 
distribution implies a certain disregard for the zonal limits which is 
probably due to temporary increase in distributional area of insect 
life, causing a temporary invasion by bats from the lesser altitudes. 
As recorded by Mrs. Grinnell, of sixty-one bats of the race Myotis 
yumanensis sociahilis collected at Fort Tejon, July 21 to 25, all the 
adults were females, thus indicating, as Mrs. Grinnell suggests, ‘Hhat 
with the approach of summer the full-grown [adult] males leave the 
colony and forage singly at higher elevations.’’ That the breeding 
females are more strictly confined to their proper ^Tife zones” seems 
likely and is corroborated by our observations on Mount Whitney, 
where the few specimens taken proved to be males. It is well 
known that the upper levels of mountains abound in insects, many of 
which are wafted up by convectional diurnal air currents from below, 
so that during the midsummer period they would form an attraction 
to insectivorous bats, and thus afford cause for a local and seasonal 
invasion by the non-breeding individuals. It was unexpected that we 
should not have taken Myotis lucifugus altipetens on Mount Whitney, 
a species whose normal range includes high altitudes. 
