plot first mentioned the ants’ nests containing lice were less than 
a third as numerous as those in the plot outside. 
From the above we can only infer the disastrous effect of this 
late fall and winter plowing upon the ants themselves, and, pre¬ 
sumably, also upon the plant louse eggs they have in charge. 
It seems also quite probable that some, if not all, of the nests 
found April 18 in the experimental plots had been established 
there by worker ants in spring, and were not remnants of the 
nests previously broken up, and if this were the case the root 
lice found in them had doubtless been brought in from without. 
Starvation Experiments .—April 15, 1889, twelve young root 
lice recently hatched were placed in a cavity in the moist earth, 
which was'covered with a glass slip so placed as to allow an 
examination of the interior. April 20 two of these root lice 
died; the next day half the lot were dead; April 22 only two 
were living; April 23 but one; and on April 24, nine days from 
the beginning of the experiment, all were dead. 
May 14, 1888, a number of corn root lice of various ages, 
taken from the roots of young smartweed in the field, were 
placed in a glass vial with moist earth, the mouth of the vial 
being covered with gauze. On the 18th all were still alive, but 
by the 20th all had died, the earth in the vial still remaining 
moist. 
April 30, 1890, a number of eggs were placed in a cavity in 
sterilized earth and left to themselves. May 1 one young louse 
aopeared from the only egg of the lot which hatched, and May 
3 this one was dead. It appeared from the foregoing that 
voung of this species hatching in the earth and kept without 
food would die in from two to nine days. 
► As a field application of this fact, an attempt was made April 
16, 1889, to starve the young lice in the ground by keeping- 
down the growth of young weeds. A piece of ground was thor¬ 
oughly harrowed in two directions with a cutaway disk harrow, 
and the weedier parts of the plot, several times additional 
April 20, however, ants and lice were found both within and 
without the harrowed strip; but the ants had no plant-louse 
eggs in their possession where the ground had been harrowed. 
The result of this treatment was not especially encouraging, the 
young weeds sprouting so freely and abundantly in the moist 
earth, to a depth of four or five inches, that it seemed impossi¬ 
ble to reduce the food supply of the lice to any considerable 
extent by mechanical methods. 
Our present knowledge of effective economic procedure for the 
corn root aphis may be summarized in the form of the follow¬ 
ing recommendations: (1) that the fertility of the ground 
should be maintained as a general safeguard, and that cultiva¬ 
tion should be so managed—especially that of the lower parts 
* By an unfortunate oversight no mention was made in the notes on the second experi¬ 
ment, of rootflice in either the plowed strip or check. 
