THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 65 
EFFECT OF CORROSIVE SUBLIMATE. 
A poisonous emanation appears to be given off by the mercuric 
shellac band which is very injurious to the ants, as one example of 
the behavior of ants which have crossed it will illustrate. An ant 
attempting to cross one of these bands suddenly stopped when part 
way across and began to stroke the antennae with the first pair of 
legs. It remained on the band about 1-J minutes, turning slowly 
about, stroking the antennae, and drawing the legs between the 
mandibles. It then slowly retraced its steps off the band and moved 
aimlessly about for a time, often getting in the way of other ants. 
Soon one of these stopped and took hold of one of its antennae. 
This made it active long enough to disengage itself, when it again 
became sluggish and wandered aimlessly. This continued as long 
as it was watched — about 10 minutes. Other ants, some of which 
were themselves sick, were trying to drag their dizzy fellows to a 
shelter. Most of the sick ants finally became very sluggish and many 
of them fell from the tree. 
TRAPPING THE ARGENTINE ANT IN LOUISIANA. 
By far the best and the only practical means of destroying the 
Argentine ant in the orange groves of Louisiana is by trapping. 
The discovery that the ants would collect in large numbers in boxes 
of decaying vegetation in winter was first made by Messrs. Newell 
and Barber, who described a method of destroying them based on 
this fact. 1 The method of trapping about to be described differs 
in several important respects, however, from that recommended by 
these gentlemen. It is based mainly upon the fact that a very slight 
rain at any season of the year will cause the ant colonies to come out 
of the ground, where most of them nest, and seek dry, sheltered 
places. 
Effect of Rains Upon the Ants. 
The favorite rainy-weather nesting places of the ants are under 
loose boards, piles of lumber, boxes, logs, sacks, and pieces of cloth, 
piles of bricks, piles of dead weeds, under and in the sides of build- 
ings, etc. They also preferably seek high ground, and, other condi- 
tions being equal, the largest colonies will be found on the ditch 
banks and the high ground at the base of the trees. Just as foraging 
workers often complete a partial natural shelter found upon a tree 
or elsewhere by making walls of bits of trash, the ants often build 
elaborate structures of soil particles and trash under the loose boards 
i y and other shelters found on or near the ground. 
The idea of using the traps about to be described was first sug- 
gested by the behavior of the ant colonies in an orange orchard in 
*Op. cit., p. 95-96. 
