THE LIFE OF MAMMALS 
ing persons, and without awakening them withdraw an annoy- 
ing quantity of blood. 
For the many curious adaptations and habits of the hundreds 
of other kinds of bats, the reader must be sent to the larger 
zodlogics, and to the writings of Dobson,* the leading authority 
on the group. A capital account of bats and the superstitions 
about them has been written by Dr. Oswald.”° In general, the 
bats of this division are night flyers, and retire during the day 
to dark places, such as 
hollow trees, caves, and 
the crevices and cham- 
bers of old buildings 
= and of ruins. There 
they hang by their heels 
to the rocks and walls, 
sometimes in compact 
masses which burst into 
a cloud of frightened 
creatures when the 
haunt is invaded; and 
the acrid odor of their 
bodies, and of the deposits of their valuable coal-black guano 
(which has become an article of commerce), is almost overpower- 
ing. The rock tombs and temples of India, and the tombs and 
pyramids of Egypt, are thronged with various bats.® 
Egypt seems peculiarly well suited to bats, by its 
warm climate and clear sky at night, and the bat guano from 
certain caves is valuable in agriculture. In warm countries 
these retreats are occupied the year round; in colder countries 
some species regularly migrate to the South in winter, as is the 
practice of some bats of the United States, but most sleep away 
the cold months when no insects are flying. 
The food of most bats consists of insects caught on the wing 
at dusk and dawn, and they do us much service by their agile 
62 
Brownell, Phot. 
A BAT IN A SLEEPING POSITION. 
Tomb Bats. 
