82 
MAMMALIA. 
(measuring 400mm. in extent) and differed from the adults chiefly 
in being' a little lighter colored. 
o o 
Zaclock Thompson, in his paper upon the mammals of Vermont, 
speaks thus of this species : “The only Vermont specimen, which 
I have examined, and that from which the preceding description 
was drawn, was sent me alive by my friend, David Reed, Esq., of 
Colchester. It was taken at his place in Colchester, the latter part 
of October, 1841, and was kept alive for some time in a large willow 
basket with a flat cover of the same material. On opening the 
basket, he was almost invariably found suspended by his hind claws 
from the central part of the cover. When the basket was open, 
he manifested little fear, or disposition to fly, or get away, during 
the day time, but in the evening would readily mount on the wing 
and fly about the room, and on lighting always suspended himself 
by his hind claws with his head downward. He ate fearlessly and 
voraciously of fresh meat when offered to him, but could not be 
made to eat the common house fly.”* 
Idle hour at which bats leave their retreats to begun their noc- 
turnal excursions is governed, first, by the latitude, longitude, and 
altitude of the locality, and the time of the year ; and, second, by 
the character of the sky (whether clear or overcast), and the ex- 
posure — those living along the southern and eastern borders of 
woodlands, and in dark ravines, appearing earlier than those whose 
hiding-places face the setting sun. In other words, the time at 
which bats appear depends solely upon the degree of darkness. 
Hence it follows that their nightly exodus, in a given locality, 
does not take place at a fixed period after the disappearance of the 
sun ; for, during the first part of October, in this latitude, the dark- 
ness is as great half an hour after sunset as it is an hour after three 
months earlier. Therefore, in estimating the exact hour at which 
bats are to be expected at any stated date, it is necessary not only 
to consider the time the sun sets, but also to take into account the 
*■ Natural and Civil History of Vermont, 1842, p. 25. 
