

LIFE HISTORY OF CARPENTER ANT. 1 95 



The first aphid appeared on the tree about May I, 1906, and 

 when I first noticed it a single ant was attending it. Gradually, 

 as the colony of aphids increased in numbers and spread over the 

 tree, the number of ants to be seen there also increased propor- 

 tionally. My attention was very early called to the fact that, 

 although some of the larger workers (size no. 2, Fig. 3) were often 

 about the base of the tree, they never ascended to the aphids. 

 The work of attending the aphids was performed entirely by 

 workers of size no. 3. After the aphids became abundant I re- 

 peatedly saw ants of this size coming from the hole in the ground 

 and ascending the tree to the aphids, and later returning. At 

 the same time numerous workers of size no. 2 were coming from 

 the nest and entering the hole in the ground, and others of this 

 size were leaving this hole for the nest. On the evening of July 

 20, I made an observation which explained these actions. A 

 no. 3 came down the tree and before entering the ground was 

 accosted by a no. 2 and responded by giving up to her larger 

 sister apparently all that she had gathered above. While their 

 mandibles were interlocked in the process of transferring food the 

 abdomen of the smaller one kept up a constant quivering, jerking 

 motion, seemingly in an effort to regurgitate the last drop of 

 food in her body. After this was over the smaller ones returned 

 to the aphids, and the larger one entered the apartment in the 

 ground as if not yet satisfied to return to the rest. This led me 

 to construct the artificial chamber mentioned above and in this I 

 have seen this process repeated many times. I find, however, 

 that it is seldom that the no. 3 gives all the food that she has to 

 offer to the first no. 2 that approaches her. During the daytime 

 when only very few of the ants were active, a large number of 

 the smaller workers were at rest in the quarters I had constructed 

 for them and not much exchange of food was going on, but 

 when I saw them here just after they had begun their evening's 

 activities, or examined this chamber by means of a light, after 

 dark, as many as two thirds of those in the chamber were paired 

 off in the act of exchanging food. At these times, between the 

 aphid tree and the nest was a caravan of workers going and com- 

 ing, and these were very largely, though not wholly, of size no. 

 2. Those returning to the nest had their abdomens distended 



