74 THE ARGENTINE ANT. 
All immature stages of the ant were present in abundance. On March 
14 the cover to one of the living chambers was raised and one of the 
mite-infested larvae was dropped in among the workers and larvae in 
the formicary. The workers set to work immediately to kill the 
hundreds of mites. The larval mites were picked up in the workers' 
mandibles, chewed a bit and then thrown aside. Adult mites were 
seized by the legs and vigorously pulled until they released their hold 
on the wasp larvae, after which the workers would crush them in their 
mandibles. However, the subsequent developments were entirely 
unexpected. A worker was seen to mount the wasp larva, eagerly 
destroying mites and becoming at the same time covered with a dozen 
or more of the mite larvae. Within a minute the worker desisted 
from destruction of the mites about her and turned her attention to 
the ones on her body, trying to dislodge them by rubbing head and 
abdomen with her legs. Failing thus to get rid of them, she resorted 
to various gymnastic performances, such as jumping and rolling over. 
Soon afterwards her movements became slow and feeble and finally 
ceased entirely, it being evident that she had either been killed or 
paralyzed by the bites of the larval mites. Observations were sus- 
pended until March 18, when it was found that the adults and larvae 
of Pediculoides were greatly reduced in numbers. No mites could be 
seen on an}" of the ant larvae or pupae, and all of the latter had been 
removed from the chamber where the mites were introduced. 
The workers hi leaving the cage to forage were compelled to pass 
through the infested chamber, but in doing so they made the widest 
possible detour about the mite-infested material. This status of 
affairs continued for some time, the mites gradually decreasing in 
numbers until by April 28 they had all disappeared. On tins date 
cultures of the mite were again introduced into the colony, but in 
much greater quantities than before. A spoonful of mite-infested 
wasp larvae was placed in each chamber of the formicary. The ants 
did not this time attempt to kill the mites, but inside of two minutes 
after the introduction of the latter the colony had completely deserted 
the formicary, taking with it all eggs, larvae, and pupae. Not being 
able to find other suitable quarters on account of the water surround- 
ing the formicary, the ants on the following day decided to return to 
the nest. They attempted to remove the Pediculoides, but the mor- 
tality among the workers was heavy, many being carried out at the 
entrance. On the following day the number of dead workers was too 
great for removal, and many of them remained in the cage. The con- 
tinual warfare against the mites continued for several days, the ant 
colony becoming by May 6 severely depleted in workers as well as 
in larvae, some of which were killed by the mites. At the same time 
it was evident that the Pediculoides were being destroyed much more 
rapidly than they could increase. After May 6 the ant colony ap- 
