74 THE AROENTINE 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 larva> 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 larvip, 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 wdth 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 

 ])aralyzed 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 any of the ant larvae or pupae, and all of the latter had been 

 removed from the chamber where the mites were introduced. 



The workers in 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 disa])peared. On this 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 liatl completely deserted 

 the formicary, taking with it all eggs, larvae, and ])upae. Not being 

 able to find other suitable quarters on account of tJie 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- 



