1878. | Mound-Making Ants of the Alleghenies. 433 
ered over except one door or round hole near the top. The 
work progressed by the continuous addition of earth pellets 
to the outer edge. The pellets were carried in the mandibles of 
the ants, and were usually pressed into position. The springing 
of the arch was plainly seen, the two sides slowly approaching 
each other in irregular lines as shown at aa. Gradually two 
points drew nearer and nearer, until they well-nigh touched. It 
was quite exciting to watch now the delicate manipulation of the 
architects. Here comes a worker with pellet of larger.size; she 
climbs the arch, reaches over, holding the while by her hind 
feet, and drops the ball of soil into the breach. The bridge is 
made. And now with surprising rapidity it is widened until the 
roof of the arch assumes the appearance indicated at 6 4. Circu- 
lar openings or doors are habitually left in the work, through 
which the ants are moving back and forth, apparently working 
upon the inside to strengthen the arch. As sections of the build- 
ing are completed these doors are closed, so that they are 
plainly but temporary arrangements for the convenience of the 
masons. 
On other parts of the foundation similar structures were going 
up. At 2, Fig. 4, was a section of a vertical column, one side of 
which had been cut away. It was two inches high, and one inch 
across. The ants were working upon this in the same manner as 
described above. They built not only from the bottom up, but 
from the sides across. The central opening in the figure was 
finally closed, leaving, when the work ended, the opening at the 
foot of the column. The circular gallery thus enclosed was one- 
half inch in diameter, which is about the usual dimensions. The 
work of construction was not confined to the space which, as in 
the above cases, was the original site of the cone. Having occa- 
sion to lift up a fragment half the size of one’s head, which had 
been thrown to one side, I saw that the section had already been 
made the nucleus of a new mound. Columns, corridors and 
halls, corresponding closely with those outlined upon the under 
face of the fragment, had been erected, which were thus quite 
united to the fragment. In one of the halls was a small collec- 
tion of dead ants. The greater portion of one day was spént in 
studying and recording the work upon this one hill. Other draw- 
ings were made from different positions, but the method and 
result were the same. As the activity occasioned by the shower 
