16 
RESULTS OF THE EXPERIMENT. FIRST INSPECTION 
The first general inspection of the field was made by Mr. Kelly 
May 28 to 30, when 800 hills were dug up in the various plots and the 
ants and root-lice were carefully counted.* Two hundred and fifty of 
these hills were from the check plots, 100 each from the principal 
experimental plots — those with carbolic acid, kerosene, formalin, and 
oil of lemon — and fifty each from the three remaining plots whose 
seed had been treated with sulphur, "Rex Dip," and' chlorid of lime. 
Percentages of hills infested tq days after planting. — At this time, 
a month after the plowing of the field and 19 days after planting, 
57 percent of the 250 hills dug up in the check plots were infested 
by ants. The corresponding averages for each of the four principal 
experimental plots were as follows : oil of lemon, 23 percent infested ; 
kerosene, 31 percent; formalin, 3Z percent; and carbolic acid, 49 per- 
cent. The ratios for the less important experiments, from each of 
which 50 hills were dug up, were 54 percent for the sulphur plot, 70 
percent for the "Rex Dip," and 48 percent for the chlorid of lime. 
Otherwise stated using the condition of the check plot as a basis of 
comparison, the plot treated with the oil of lemon showed an improve- 
ment of 60 percent in number of hills infested by ants ; the kerosene 
plot, a 46 percent improvement ; the formalin plot, 42 percent ; and 
the carbolic acid plot, 14 percent. The three other plots showed no 
improvement except possibly the chlorid of lime. 
Not all the hills containing ants at this time contained root-lice 
also, but there were no root-lice where there were no ants. The ratios 
of infestation of corn hills by the root-aphis for the five plots were 
as follows: checks, 53 percent; oil of lemon, 14 percent; kerosene, 
20 percent ; formalin, 28 percent, and carbolic acid, 39 percent. The 
corresponding ratios of improvement in respect to aphis infestation 
were these: oil of lemon, a benefit of 74 percent; kerosene, 62 per- 
cent ; formalin, 47 percent ; and carbolic acid, 26 percent. 
It is a suggestive fact that while the infested hills of the checks 
contained an average of 21 ant larvse to the hill, none of the hills 
treated with the three most odorous substances, oil of lemon, kerosene, 
and carbolic acid, contained so much as a single larval ant. In the 
formalin plot, however, there were about as many larvse to the in- 
fested hill as in the checks. As the ants take assiduous and anxious 
care of their young, the absence of larvse from the treated hills, even 
where the workers themselves were numerous, is evidence that con- 
ditions there were oflFensive to the ants. 
In view of the observed effect of an overdose of kerosene on the 
young plant, as described in the earlier part of this article, it is im- 
portant to note that no dwarfing or distortion of the corn plants was 
seen in any of these experiments. 
Average numbers of insects ip days after planting. — Turning now 
to the number of both kinds of insects in these plots, irrespective of 
*The owner of this field was paid at an agreed rate for all hills dvig up or injured in 
the course of our experiments. 
