THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 69 
After the eighth fumigation, February 27, 1915, there was very 
decided reduction in the number of ants in the orchard, and the fore- 
man of the place remarked that the ants were getting very scarce in 
the block. Only straggling workers occurred in a few of the traps 
from this time until the next fumigation, June 7. On March 25 
examination of 30 orange trees revealed only one scout ant, and it 
was reported that there were no more ants about. A ranch hand said 
he had uncovered only three nests in plowing the entire block, while 
in a neighboring orchard (which had been treated for ants by the 
flooding method for three years or longer) he had raised so many 
he could not keep track of them. On the same date the ants were 
extremely numerous in the orange trees in an adjoining grove. 
A further examination on April 16 showed ants to be present on 
only 1 in 40 trees, and then not numerous enough to form trails. 
There were no ants at the blossoms or at the numerous aphids on the 
trees. Some large umbrella trees, which usually had from six to eight 
large trails, were absolutely free from ants. In the house it was no 
longer necessary to isolate food supplies, beds, etc., from the ants, 
from which there was not the slightest further annoyance, as stated 
by both the foreman and his wife. In the upper portion of the same 
property, about 90 rows from the experimental block, on the con- 
trary, the ants were running in heavy trails up all the trees and were 
numerous in the blossoms and at aphids. 
After the February fumigation another was not warranted for 
about three and one-half months, or until June 7, when 21 of the 
traps contained sufficiently large colonies to seem to warrant their 
destruction. The killing of queens had been reduced from nearly 
300,000 in each of the first three or four fumigations to less than 
5,000, and, of course, all the other stages had been comparably 
reduced. The experiment was a complete success, for it reduced the 
ants to negligible numbers. 
The following rough but not widely erroneous estimates will give 
an idea of the populousness of the ants in this orchard: The total 
estimated number of queens killed, as reference to Table VII will 
show, was 1,307,222. The workers and young must be estimated by 
volume. In the first four fumigations every trap fumigated con- 
tained fully one-half gallon of ants in all stages, and in each of the 
succeeding five nearly a quart. The total number of traps fumigated 
in the first four operations was 1,568; therefore 784 gallons, or about 
15J barrels, of ants were destroyed. In the remaining five fumiga- 
tions there were 1,543 traps; therefore about 385 gallons, or about 
7J barrels, of ants were destroyed. The bulk of the ants destroyed 
in this work, therefore, would be almost great enough to fill twenty- 
three 50-gallcn barrels. 
