82 THE ARGENTINE ANT. 
A solution of potassium cyanid was made at the strength of 
1 ounce of 98 per cent cyanid to 1 gallon of water. The site selected 
for the experiment was the area surrounding a few small cotton 
plants which were heavily infested with the cotton louse, Aphis 
gossypii Glov. Around the plants the earth was literally honey- 
combed by numerous small colonies of the Argentine ant, the workers 
of which were in constant attendance upon the aphides. The 
experiment was made at 11 a. m. on a bright day, with the tempera- 
ture at about 77° F., when the workers were busily visiting the lice 
and foraging elsewhere for food and when the activities of the colonies 
were at about a maximum. The solution was sprayed onto the 
trails of traveling ants and the ground itself was sprayed until ^ 
thoroughly wet with the solution. By the time the spraying was 
completed the odor of the cyanid was so strong as to affect the ] 
operator. In spite of this the solution did not immediately kill the 
workers with which it came in contact, but they appeared to suc- 
cumb within about five minutes after the spraying. Five hours 
after the spraying the odor of cyanid was still very strong and the 
number of dead workers on the surface of the ground fully equaled, 
or exceeded, the number of living ones in sight at the time of spraying. 
Many live workers were busily engaged in carrying away the dead. 
The ground was examined and thousands of living ants in all stages — 
workers, pupae, larvae, and eggs — were found less than half an inch 
below the surface. Two days later the area was again examined 
and the ant colonies were apparently as populous as ever. This 
and other experiments seemed to demonstrate the impracticability ~~ 
of using this solution for destruction of the colonies, particularly as 
the earth would have to be treated with a sufficient amount of the 
solution to saturate it thoroughly to a depth of several inches. This * 
would probably destroy all vegetation, would be expensive, and 
would involve the risk of injury to or loss of life by the operator and 
others. For species constructing compact nests having single or "* 
few openings the solution is doubtless effective but, owing to the ^j 
multitudinous openings and galleries of the Argentine ant nest, 
destruction could be accomplished only by the use of enormous 
quantities of the solution. 
The resistance of this species to hydrocyanic-acid gas was well 
illustrated in experiments made hi attempting to fumigate the 
Winter trap-boxes in orange groves. These trap-boxes are described^ 
more in detail on pages 95-96. They were about 2 feet wide, 2 feet 
high, and 3 feet long, made of rough lumber and filled with decaving % ' 
cottonseed and hay. During the winter months these boxes con- 
tained enormous colonies. For fumigating them to destroy these 
colonies galvanized-iron covers were made (see Plate XII) which 
would fit over them easily. A 6-inch hole was made in the top of each - 
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