86 
Psyche 
[April 
at the same date and one-half removed for study, was found in 
July completely regenerated . and perfect. The ants can thus 
accomplish much more work in a given time than they would 
without the stimulus of destructive injury to the mound. 
The actual bulk of the mound at the end of nineteen years 
of work by the ants of this community is about 30 cu. ft., and 
was thus accumulated at the average rate of about 2 cu. ft. per 
year. The table shows the actual slow growth of the first years 
and the rapid growth of some of the later years. The number of 
ants is unfortunately not known, but they were very few in the 
first years and very many indeed in the later years. The nascent 
community accumulated but few cubic inches per day, the mature 
colony fifty to one hundred or more. As the single ant is but 
1-630 part of a cubic inch the labor done is relatively very great 
and all the work seemed to be done by individuals without aid 
of fellows. Such facts led McCook to the estimation that con- 
sidering the bulk and the speed of construction of the ant mound 
as compared with the bulk and supposed speed of construction 
of the pyramids of Egypt, the ant may be much more efficient 
than man, in fact nearly 700 times as powerful a laborer. 
In the building of the mound the first two or three years 
seem to be exclusively years of mining operations, bringing up 
the earth from the shafts below ground; but after that period 
the ants begin to construct the mound from two classes of 
materials. Not only is the excavation process continued and 
the removed material added to the pile, but there is more and 
more, bringing in of surface material, both surface soil and bits of 
organic matter such as sticks, straws, leaves and other light par- 
ticles. In the early stages of mound growth the cast up mouth- 
fuls of subsoil merely accumulate in a loose pile, but the weather 
compacts them and a denser mass results within which the ants 
begin to excavate their tunnels above the natural surface of the 
ground. Thus mound No. 2 had, when four years old, but few 
internal tunnels merely suggesting the complex labyrinth of the 
mature mound. 
Incidentally it may be noted that in this region no trees 
seem to be killed by the ants, though that has been described in 
New England; but the ants keep the Japanese ivy from growing 
