498 ENTOMOLOGICAL SOCIETY 



served a small worker of Camponotus pennsylvanicus, head 

 downwards, about five feet above the ground, which had evi 

 dently come down from a foraging expedition, collecting the 

 honey-dew or nectar of Phyllaphis fagi, which was very abun 

 dant on this tree. As a rule, these ants are very active in ascend 

 ing and descending trees ; this particular specimen, however, had 

 stopped short for some mysterious reason and remained in this 

 position while I was watching it and kept motionless until I 

 touched it. The poor creature appeared to be tired and sleepy, 

 and moved rather aimlessly and laboriously to one side on being 

 touched. Being urged again, it moved a short distance in the 

 opposite direction, seemingly in a trance or having lost the mem 

 ory of its home. The action of this specimen appeared rather 

 remarkable to me, since this species is very active, especially 

 when disturbed, when it darts along at a rapid gait ; it seemed to 

 have lost control of its limbs and movements of its body. The 

 head was drooping, as if of no use to its owner, though the antennae 

 were still moving. In fact, it seemed as if it had lost its head. 

 In order to discover something of the cause of this ailment I 

 transferred it to a large vial and took it home. After an hour or 

 two of resting, after reaching my home, I examined the vial to 

 learn how my little sufferer was getting along, but found to my 

 surprise that the poor thing was minus a head, though still alive 

 and quite as active as before on being urged to move about. Fur 

 ther investigations of the contents of the vial disclosed the head 

 at the farther end of the vial, minus its antennas and mouth parts, 

 which were some distance in front of the head, and, while exam 

 ining the skull of the ant through the glass, I observed the ante 

 rior part of a Dipterous larva protruding from the anterior 

 opening of the shell, swaying back and forward, but soon to re 

 tire into the empty shell of the head. Next morning the poor 

 victim was dead. 



Having kept the specimen reasonably damp, I was rewarded 

 and delighted to find on the morning of the 2ist of September, 

 or 17 days after the head had been cut oft', a very handsome, ex 

 tremely active and agile little fly in the vial, scurrying along 

 with extremely rapid motions, only to stop now and then to clean 

 itself and to exercise its horny genital apparatus in anticipation 

 of the important work to be performed by it. 



To continue my observations, and possibly to obtain additional 

 infested ants, I went again to the same locality on the 24th of 

 September, but failed utterly in discovering additional specimens 

 showing symptoms of being infested. Being disappointed, and 

 sitting down near the base of a beech tree badlv infested with 

 Pemphigus hnbrlcaria^ suspecting that there might be a colony 

 of this ant at or near its base, I removed the loose bark, just above 

 the ground, and found that I was not mistaken, for, as soon as it 



