6 ARCHITECTURE OF ANTS. 
of the sun, or retain it in the interior. 
‘The mass of the different materials of 
which it is composed, always presents a 
circular dome, whose base, often covered 
with earth and pebbles, forms a cone, 
above which the wooden portion of the 
building is erected in the form of a 
sugar loaf. But this is simply the exterior 
covering of the ant-hill; the most con- 
siderable portion is hidden from our sight, 
descending to a depth of greater or less 
extent. Avenues constructed very care- 
fully of an irregular funnel shape conduct 
from the roof to the interior. Their 
number depends upon the population of 
the nest and its extent. The entrance to 
the nest is more or less considerable. 
We sometimes find a spacious aperture at 
the top, but more frequently, several 
apertures of nearly equal size, around 
-which are many narrow passages, symme- 
trically and circularly disposed, which 
extend even to the base of their habita- 
tion. 
These several apertures were necessary 
