THE ARGENTINE ANT IN RELATION TO CITRUS GROVES. 55 
sooty and green mold. Again, it seems to be primarily the ants 
that are protected, as they await the excretion from the mealybugs. 
Perhaps the clearest proof that these shelters are built mainly in 
response to the needs of resting worker ants is the fact that under 
certain circumstances they will be built on the tables supporting 
artificial formicaries, where no scales or aphids occur. Six formi- 
caries of the Janet type were kept on small tables set in pans of oil 
(see PL IV). Food, poisoned sirup, and water were placed on the 
tables outside the formicaries. When sick from a poison, the ants 
are very eager for water with which, perhaps, to wash out the crops, 
and numerous sick ants constantly hung about the water plate. 
Whenever sufficient trash was allowed them they would build a 
shelter tent from the edge of the formicary to that of the water dish, 
and this tent always would be full of ants regurgitating the poison 
and cleaning each other's mouth parts. 
THE HABIT OF BURYING NOXIOUS SUBSTANCES. 
Another activity of the ant somewhat along this line is the habit 
of piling debris upon noxious substances. On rare occasions they 
bridge bands of sticky material placed on the tree trunks in this 
manner. Generally, however, this is done only where the substance 
is actually injurious. In the field poison tests frequent cases were 
observed where the shelter-constructing and trash-piling habit 
merged into one. When foraging at the poison jars it was of common 
occurrence for the ants to construct out of particles of soft soil 
elaborate shelters about the sides of the jars, and sometimes com- 
pletely over them. (PL I.) As they learned the effects of the 
sirup they often would deposit more and more particles on the 
sponge within the jar and finally fill the entrance hole completely. 
In one case, for example, they partly covered the sponge and filled 
the entrance to one of the jars nine times in the course of several 
months. In an experiment with moth balls placed in a saucer with 
sirup poured over them, the ants eagerly took the sirup for a week, 
at the end of which time there were large numbers of dead in the 
mixture. The ants then became engaged principally in removing 
the dead. The saucer had been placed on a piece of white crepe 
paper, and when this accidentally got wet the ants bit out particles 
of the paper and constructed an elaborate shelter completely around 
the edge of the saucer. Under this large numbers of workers might 
- be found at all times. As they continued to feed and get poisoned, 
however, they began piling bits of paper on the moth balls and 
finally completely covered them with the " confetti." 
