176 
JOURNAL OF MAMMALOGY 
building, where one would lay odds that they would be cooked to a crisp 
by the mid-day sun, but at late dusk out they swarm through a hole 
that seems too small for a shrew to pass, and away into the gathering 
darkness. When flying, their long, pointed wings are diagnostic, and 
one soon learns to recognize them. I have watched them at play above 
a pool when almost too dark to distinguish their forms, and at a time 
of year when their antics could not be interpreted as a form of court- 
ship. As I sat facing the pale, western sky, one would approach swiftly 
— they are speedy fliers — give chase to another, and both would do a 
nose-dive to the surface of the water and rise up to the original height 
without lessening speed. Sometimes one v^^ould tire of the sport while 
the other continued alone; or half a dozen would join the game, diving 
from as many directions. 
If there is not a crack for them to back into when disturbed they 
are quite ready to fly, or to flutter to the floor and scurry to shelter 
with almost the agility and speed of a mouse. When thus ‘‘running’^ 
their folded wings are kicked up in the rear, giving to their gait a ludi- 
crous, hand-over-hand appearance. When alighting the movements are 
so quick that the animals appear literally to dive into a hole; and 
when no hole is available, they will catch on to a support by the thumbs 
and quickly shift head downwards. This is the normal method of 
alighting used by bats. 
A LIST OF THE COLONIES VISITED 
.1. An abandoned mine two miles north of Potholes, Imperial County, con- 
sisting of a very extensive series of connecting chambers. One or two hundred 
leaf-noses, evidently all males, and a single Yuma bat, May 14. Visited with L. 
Little. 
2. Old Senator Mine, 6 miles north of Potholes, Imperial County. On the one 
and two hundred foot levels were a colony of a hundred female lump-noses 
with small young, and some six hundred Yuma bats, mostly females — one of 
which contained an embryo May 14, 1918. On April 13, 1916, D. R. Dickey 
found only a dozen lump-noses here in addition to the yuma bats, and by May 
10 the former had disappeared and their places been taken by seventy-five leaf- 
noses. Visited with L. Little. 
3. A series of old tidal caves at the base of the hills southwest of Thermal, 
Riverside County. No bats present January 26, but these caves are famous for 
their summer colonies of leaf-noses and both J. Gritinell and D. R. Dickey have 
secured bats from the caves in this series. 
4. Extensive cave in the hills two miles north of Owensmouth, Los Angeles 
County, holding 6 leaf-noses April 6, none June 4, and about 30 December 14. 
There had been many cold nights prior to the last date and, as the end of the 
