THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 67 
bent into two right angles, forming two sides and the top, and two 
pieces 13^ by 13£ inches, forming the other two sides. The edges of 
the latter two pieces are folded inwardly over those of the first piece 
and hammered tightly together. Covers with soldered, instead of 
hammered, seams are preferable, however, unless the latter are very 
well made. The completed cover should measure 12J by 12^ by 12£ 
inches inside, leaving a margin of J inch to turn down all around 
the outside to reinforce the open edge. 
Results of Ant-Teapping Experiment. 
The experiment, the results of which are about to be briefly stated, 
was conducted in a block of approximately 19 acres 1 of bearing 
orange trees completely overrun with ants, located at Happy Jack, 
La. The traps, numbering 415 in all, or about 22 per acre, were set 
April 21-22, 1914. A trap was placed on a slight elevation at the 
outer edge of the spread of every second tree each way, or one trap 
to each four trees. Tests of various kinds of filler had shown pre- 
viously that the best for summer was dry grass and weeds ; for winter, 
equal parts of decaying manure and dry grass and weeds. From the 
time of setting the traps until the first rain, about 56 days, the ants 
were nesting almost wholly at from 8 inches to 1J feet in the ground. 
Even after such a period of prolonged drought, however, a rain of 
about 0.2 inch, occurring June 18, 1914, was sufficient to drive them 
into the traps in large numbers. 
Tests of different strengths of carbon disulphid and strong am- 
monia water as fumigants proved that 12 ounces per trap of the 
ammonia was satisfactory. The carbon disulphid, however, proved 
satisfactory at as little as 2 fluid ounces per trap, allowing the traps 
to fumigate for 1 hour. 
The first fumigation was started June 23, at which time it was nec- 
essary to fumigate 334 of the traps, only those which contained large 
and complete colonies being disturbed. The second, third, and 
fourth fumigations were started July 21, August 26, and September 
28, respectively, completing the summer's killing. A solid mass of 
ants, in all stages, nearly as large as a man's hat, was killed in each 
trap each time. The workers and even the queens were so numerous 
that it was entirely out of the question to separate and count them in 
any large number of the traps (see PL VI). The queens, however, 
were counted each time in one or two traps with an average killing, 
and in this way it was estimated that 1,161,323 queens were killed in 
these first four or summer fumigations, 600,000 in the first two, 
295,895 in the third, and 265,428 in the fourth. All of the traps were 
1 All references to the acre are to the " square acre," not the " acre front." 
