1925 ] 
Growth of Ant Mounds 
85 
through some years but eventually is all washed away. This 
particular colony of ants had a very difficult soil to deal with 
and the progress made at first was much behind that reported 
by McCook in a region of sandy wood soil. Like all loosely 
piled earth, the nest must suffer shrinking and condensation 
from settling when this is not actively counteracted by ant 
work. 
During the years that this mound had been forming others 
were made in the same soil nearby and these had grown to about 
the same dimensions. Two little mounds were started near the 
above mound and may well have been colonial offspring from it. 
As far as measured they have the same very slow rate of starting 
and are in the same soil. The following table shows these young 
mounds starting on their long period of trial, at the same cautious 
pace: 
Nest No. 2 
Width 
Contents 
cu. ft. 
Material 
1921-8-26 
4-5 
8-10 
•054 
Subsoil, clay 
1922-7-22 
3 
1 1 
•054 
Subsoil, clay 
1922-9-10 
3 
1 1 x 14 
.070 
Earth 
1923-7-8 
4 
14 x 14 
•ii 7 
Earth and sticks 
1924-1-27 
3 
15 X 15 
. 101 
Earth and sticks 
1924-7-20 
4-5 
29 x 17 
.421 
Subsoil 
1924-12-20 
5-5 
Nest No. 3 
18 x 18 
.267 
Coarse particles and sticks 
1921-9-9 
1922 
2 
13 X 7 
.030 
Subsoil, Sandy 
1923-7-8 
2 
11x5 
.019 
Subsoil, sandy 
1924-7-20 
6-5 
19 X 16 
•045 
Clay, subsoil, sticks 
1924-12-20 
6 
20 X l8 
.328 
Very coarse particles and 
sticks 
The rate of growth under the natural conditions prevailing 
is but slow, yet when injury is done to the mound the repair 
work and reconstruction results in very rapid new formation. 
Thus the little mound No. 2 was cut into two with a saw when 
frozen, January 27, 1924, and the half carried away, yet by the 
following July the ants had made good the loss and added to the 
former height, width and bulk as shown in the table. In the 
same way a full grown or adult mound cut into two when frozen 
