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 PI. 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. (PI. 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." 



