58 Ce coe, toe ms, 
this relation of all but the third and fourth just mentioned* is, how- 
ever, so rare that they need receive here no more than this passing men- 
tion, especially as their services to the aphis are, so far as observed, the 
same in character and value as those of the much more abundant species. 
The fact has already been mentioned in this paper that the sexual 
egg-laying generation of the corn root aphis—the last to appear in fall— 
is ‘born in the galleries of the nests or homes of ants, and that here the 
sexes pair and the females drop their eggs. As one explores these nests 
in November, when the root louse eggs are being laid, he is struck with 
the relative independence of these oviparous adults, which are allowed 
to wander unattended through the burrows of their hosts as far as a foot 
or more from a corn root. We have found them, however, still feeding 
as late as November 5, and laying eggs November 21. These eggs, which 
are yellow when first deposited, but soon become shining black, and 
turn. green just before hatching, are at first scattered here and there, as 
it happens, but are finally gathered by the ants for the winter in little 
heaps and stored in their galleries, or sometimes in chambers made by 
widening the gallery as if for storage purposes. If a nest is disturbed, 
the ants will commonly seize the aphis eggs—often several at a grasp— 
and carry them away. In winter they are taken to the deepest parts of 
the nests (six or seven inches below the surface in some cases observed ) 
as if for some partial protection against frost; but on bright days in 
spring they are brought up, sometimes within half an inch or less of 
the surface, sometimes even scattered about in the sunshine, and carried 
back again at night—a practice probably to be understood as a means . 
of hastening their hatching. T have repeatedly seen these ants in con- 
finement with a little mass of aphis eggs, turn the eggs about one by 
one with their mandibles, licking each carefully at the same time as if 
to clean the surface. These anxious cares are of course explained by the 
use the ants make of the root lice, whose excreted fluids they lap up 
greedily as soon as the young lice begin to feed. They are not, how- 
ever, wholly dependent on this food supnly, at least in early spring, as 
I have seen them kill and drag away at that season soft- bodied insect 
larve, doubtless to suck their juices out as food. This has been a some- 
what rare occurrence, however, and has rarely been noticed by us among 
ants which had plant lice in their possession. Once, however, ants of 
this species occurring abundantly in corn fields were observed September 
22 to carry bits of dead insects into their burrows, together with a living 
corn root louse. 
That the young of the first generation are helped by the ants to a 
favorable position on the roots of the plants they infest is quite beyond 
question. It is shown (1) by the fact that in many eases the aphis could 
not get access to such roots unless these had*been previously laid bare by 
the tunneling of the ants, and (2) by the behavior of ants with mines 
already constructed, when the root aphis is offered to them. We have 
repeatedly performed the experiment of starting colonies of ants on hills’ 
of corn in the insectary and exposing root lice from the field to their at- 
tentions, and in every such instance, if the colony was well established, 
* Typical Lasius niger and its barely distinguishable variety alinews are almost 
equally at home in the corn field, and do not differ noticeably in their relations to 
the corn root aphis. 
