68 
The weather during the period covered by the above experiment was. 
generally dry, but abundant rains occurred June 20 and 21, which 
seemed to dissolve the fertilizers and wash them into the ground. 
The lime, ashes, and salt experiments were entirely without effect, 
ants and plant lice occurring abundantly in all parts of the plot treated 
throughout the entire period of observation to July 28. This plot 
served consequently as a check upon the preceding experiment. 
Although the effect of the other applications seems from the above 
notes to be quite marked, the experiment is nevertheless indecisive, since 
the hills treated were not dug up when examined from time to time, but 
only searched as carefully as was possible without injuring the plants. 
July 28, when all the hills were removed they seemed, according to Mr. 
Marten’s report, to be about equally infested, all appearance of difference 
having then vanished. It will thus be seen that these experiments have 
little ‘value except as hints towards future work. The differences ob- 
served may nearly all have been due to a repellant effect of the sub- 
stances applied, in consequence of which the ants withdrew their charges 
deeper into the earth, with little diminution perhaps of the injury to the 
corn. 
Breaking up Nests of Ants. iment, begun November 
25, 1890, a strip of corn stubble three rods wide and ten rods long near 
the University premises at Champaign, was plowed six inches deep, halt 
the strip being thoroughly harrowed also. The ants’ nests among the 
corn hills were thus turned out and thoroughly broken up, except that in 
a few cases the plow did not go the full depth of the nests, but left the 
bottom undisturbed. The harrowing knocked the dirt out of the roots 
of the corn and broke up the fragments of the nests remaining in the 
elods. April 18, 1891, when the ground was again plowed, five ants’ 
nests were found in this plot and thirteen in an equal strip beside it. 
All of these outside nests contained ant larve of various sizes, while 
those inside the strip contained no ants but worker adults. Ten of the 
former lot of nests and three of the latter contained root lice also, on 
smartweed roots. 
In another precisely similar experiment, begun upon the same day 
in an adjoining field, a strip was plowed two and a half rods wide by 
twelve rods long, half of this being thoroughly harrowed, as before. The 
plowing averaged six inches in depth, but the plow ran considerably 
deeper under the corn rows, and the ants’ nests were well broken up and 
scattered. April 17 of the following spring the ground was plowed for 
corn and thoroughly examined to determine the result of the experiment. 
The part which was harrowed contained three ants’ nests, the remainder 
six; while on an equal strip adjoining, thirty were found. None in the 
strip plowed in fall contained young ants, while every one of those out- 
side contained them. Several wingless females were seen in the nests, 
one of them in the plowed strip. 
Neither the weather at the time nor that of the following winter ~ 
was especially favorable to the stiecess of such an experiment, the mer- 
cury reaching a maximum of 49° F. on the day the experiment began ; 
and the winter following—that of 1890—91—being unusually open and 
- 
