74 . ST ae 
In ordinary winter weather of the milder sort, these ants are not 
absolutely motionless, but if disturbed crawl slowly and stupidly about, 
sometimes even painfully attempting to perform their usual duties of 
restoration and repair. We haye not explored ‘heir 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 i 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 down- 
ward 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 lim- 
ited to this resource but, early in spring especially, has been found by 
us with freshly killed insects in its possession—caterpillars, carabid 
larve, and the like. Sometimes in midsummer 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 at- 
tacked 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 without 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, and 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 were seen 
dragging live chinch bugs over the ground, one of which barely showed 
signs of life, a second of which moved its legs more vigorously, while a 
third, which an ant was dragging along by the beak, seemed scarcely 
at all disabled. 
Description (Plate X., Fig. 5 and 6; and Plate XI., Fig. 1) — 
Lasius niger and its variety alienus belong to a group of small ants, 
the workers of which are about one sixth of an inch long, varying from 
yellowish brown to dark brown in color, and covered with a fine dense 
pubescence intermixed with scattered erect hairs, the surface therefore 
appearing dull or but feebly shining. The frontal area is faintly im- 
pressed, and the ocelli are indistinct. Their antenne are 12-jointed. 
the third antennal joint shortest, the succeeding joints gradually longer. 
The maxillary palpi are long and slender, six-jointed. Between the base 
of the abdomen and the thorax is a short segment compressed above into 
a flattened vertical brownish scale, not distinctly notched above. The 
anal opening is circular. er 
