goo Mound-Making Ants of the Alleghenies. [July, 
mit of the hill, but a deep trench or gallery had been preserved 
all the way across, the wall being maintained intact. Nor was 
there any appearance here of the formation of the galleries above 
described ; it was dead filling in. In one of the little hollows the 
shells of cocoons, out of which antlings had just been delivered, 
were piled up, apparently to assist in the filling. I had before 
observed these being carried from this hill and deposited on the 
stones outside. A number of straws were worked into the 
columns, evidently as'braces. A few feet from this large mound 
was a small hill, one of its off shoots, which even before the rain 
had shown much activity in construction, for the surface was cov- 
ered with fresh pellets. The shower had inspired the inmates of 
this young community with amazing zeal. 
Underground Galleries —Thus far we have been dealing with that 
part of the formicary which is above ground and is apparently 
the most considerable. There is, however, a hidden portion which 
is immense in extent, and must have vast importance in the 
economy of the community. Every hill furnishes a fair measure of 
the extent of the underground system of galleries connected there- 
with; for it is reasonably certain that the entire bulk of soil in 
each mound has been excavated and brought up from the galler- 
ies beneath the surface. The average width of the upper galler- 
ies is about three-eighths of an inch; the maximum width not 
exceeding one-half inch. The underground galleries are proba- 
bly of the same size. A glance at these mounds, therefore, at once 
gives indication that an extraordinary system of subterraneous gal- 
leries must be connected with each formicary, though I made no 
satisfactory examination into the arrangement of this system ; this 
might have been done, perhaps, by sinking a deep trench close 
to a mound and extending it for some distance. But the soil is so 
very full of stones that even thus the results might not be satisfac- 
tory. No doubt the ants descend to considerable depths, utilizing 
the stones in various ways, for example for roofs and walls, as 
they do upon the surface. It would hardly seem possible to pre- 
serve any great regularity in the course of these underground 
ways which must constantly be diverted by the stones. But they 
undoubtedly can be held to a general course, and are carried with 
great directness from point to point, when it is desired to commu- 
nicate with the trees and feeding places. I was able in one case 
to trace the extent of the galleries near the surface in the follow- ; 
