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warm. Further, there had been more than a week of warm spring 
weather previous to April 18, the mercury reaching 72° on the 9th, 75° 
on the 13th, and 77° and 78° on the 17th and 18th respectively—tem- 
peratures at which ants as active as the little Lasius niger alienus might 
well disperse themselves and begin new colonies in unoccupied ground. 
These experiments afford, perhaps, scarcely a sufficient basis for a 
final conclusion as to the economic value of this method, but so far as 
they go they are most encouraging. If we compare the treated plots 
with the check plots beside them, we find (1) that the ants’ nests in the 
former were less than a third as many as in the latter; (2) that all in 
the plowed and harrowed plots were destitute of ant larvee while in the 
cheek plots all without exception contained such larve; and (3) that in 
the single 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, presumably, also 
upon the plant louse eggs they have in charge. It scems also quite 
probable that some, if not all, of the nests found April 18 in the experi- 
mental 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 Haperiments—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 in- 
terior. April 20 two of these root lice died; the next day half of 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 ster- 
ilized earth and left to themselves. May 1 one young louse appeared - 
from the only egg of the lot which hatched, and May 3 this was dead. It 
appeared from the foregoing that young 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 
erowth of young weeds. A piece of ground was thoroughly 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, 
* By an unfortunate oversight no mention was made in the notes on the second 
experiment, of root lice in either the plowed strip or check. 
