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JOURNAL OF MAMMALOGY 
nings in late March, and they disappear about the time of the first very 
cool nights in the fall — when Nycteris may first be expected. Their flight 
is rather high, steady, and unmistakable; and they are easily shot. In 
buildings, during the spring, I have found a number of colonies com- 
posed of from a dozen to sixty individuals. They are fond of congre- 
gating in a narrow space with Nyctinomus but are apt to be found singly 
in almost any good situation. While examining a deserted building, if 
one finds a little pile of guano beneath a cranny that is just large enough 
for a single bat, a likely guess is that he has found the temporary home 
of an Eptesicus. If one waits about such a place until a few minutes 
after sunset, he may see several bats leave their retreats, one after the 
other, and fly off in a rising slant with head well elevated as is a poor- 
will’s after drinking. Each female gives birth to a single young during 
the last few days of May or the first of June. 
The pale lump-nose {Corynorhinus rafinesquii pallescens) is not as 
common on the deserts as is the leaf-nose, and I have encountered it 
but once. This was in the old Senator Mine, where we found about a 
hundred females, each with a naked young from a few days old to a 
quarter grown, clinging to the roof of a gallery at the two-hundred- 
foot level. They were in close formation but not touching one another, 
and, although not as wild as Macrotus, they were quite ready to fly. 
The only way in which we could capture them was wildly to grab at 
a bunch with both hands. In another part of the mine we found two 
single males in a semi-torpid condition, although the surrounding tem- 
perature was close to par. These bats appear to be larger than they 
really are because of their huge ears, to the formation of which and to 
the fact that they are folded away at times, other writers have called 
attention. This habit of folding the ears is indulged in whenever the 
animal is at rest and when no danger threatens. It is not limited to 
this genus, for Plecotus (a European genus) shares the pecuharity. 
When the bat is on the alert the ears are held well forward and almost 
parallel, but when all is quiet they are swung around to the side, either 
in unison or separately. Then they are “crinkled” along the outer 
or posterior edge until this forms into tiny accordeon plaits, and the 
extremities are tucked safely beneath the forearms. When the animal 
is disturbed the ears may be partly unfurled at once, but all the motions 
of this operation are slow — at about the rate of a snail’s pace. 
During the first really warm weather in early April, pallid bats 
(Antrozous pallidus pacificus) appear in numbers in the orange groves. 
Stationed in a suitable spot, one is pretty sure to see them at mid- 
