4 
which their eggs and young and the eggs of the corn root aphis 
are preserved and cared for. Here also considerable collections 
of the worker ants are usually found,—especially in winter and 
in times of summer drouth,—and in these chambers the female 
resides and lays her eggs. 
In April, May, and June the workers s^em to be most numer¬ 
ous and active. In July and August their activity 7 declines, par¬ 
ticularly in the hottest and dryest weather, although if nests be 
opened at these times the ants will be found in abundance. 
Again, in September, a period of bustling activity begins which 
continues until checked by the winter cold. 
In ordinary winter weather of the milder sort, these ants are 
not absolutely 7 motionless, but if disturbed crawl slowly and 
stupidly about, sometimes even painfully attempting to perform 
their usual duties of restoration and repair. We have not ex¬ 
plored their nests in the coldest weather, when the ground is 
frozen to a considerable depth. 
During the first warm days of spring the thoroughly awakened 
ants begin to open up their burrows to the surface, and carry 
their own eggs and young and the eggs of the plant lice in their 
possession upwards and downwards according to the varying 
warmth of different layers of the soil. When the sun is shining 
brightly in the middle of the day they bring their charges to 
the more superficial chambers of their nests, or even expose them 
on the surface, but keep them farther downward at night and in 
cold and cloudy weather. The effect of this care upon the plant- 
louse eggs is shown by the earlier hatching of those cared for by 
the ants, and by the diminished number of those which fail to 
hatch at all. 
Although this ant is evidently chiefly dependent for food upon 
the corn root aphis and other plant lice fostered by it, it is not 
strictly limited to this resource but, early in spring especially, 
has been found by us with freshly killed insects in its possession 
—caterpillars, carabid larvae, and the like. Sometimes in mid¬ 
summer also it resorts to animal food. July 16, 1884, in 
digging into a hill of corn infested by the root aphis and this 
ant, I unearthed a carabid larva. This was suddenly attacked 
by one of the ants, which pounced upon it just behind the head. 
The larva struggled vigorously, but the ant soon fastened its 
jaws on the under side of the neck, just behind the head, and a 
little to one side of the middle line. After this the struggle 
lasted only a few seconds, when the larva became completely 
quiet, and allowed this ant and another to drag it away with¬ 
out the least resistance. I watched this operation for a few 
minutes with a glass, and then put both ants and larva into 
alcohol. Although the larva did not visibly bleed when bitten, 
it was apparently dead, *^ud did not struggle at all when put 
into alcohol. 
June 2. 1891, an ant of the above species (Lasius niger) was 
found with a dead chinch bug in a wheat field, and three others 
