life history of carpenter ant. 1 97 



Food. 



The food of these ants consists principally of the so-called 

 "honey dew," of the aphids, this being supplemented by insect 

 food, and occasionally by plant juices. While they may prefer 

 some species of aphids to others, they are not limited to any one, 

 and seem to be able to make use of all species that infest the 

 aerial parts of plants. I have seen them attending aphids on 

 burdock, on wild lettuce, and on spruce trees, as well as on 

 plants whose sap has a more pleasant taste to us. The aphids 

 are not domesticated as are those of some other species of ants, 

 and I have found no aphids or aphis eggs in any of the nests that 

 I have opened. In October, when the aphids on the cottonwood 

 tree above mentioned were laying eggs, I repeatedly collected 

 leaves to which eggs were attached, and placed them near the 

 base of the nest tree and at various other places in the direct 

 path of the ants, but although I repeatedly saw the ants pass 

 directly over the eggs, they paid no attention to-them. 



So far as my observations go, their insect food is never taken 

 alive. These ants seem to live peaceably with all creatures so 

 long as the portals of their formicary are not crossed, and they 

 give free admission here to a good many special guests. They 

 do not even attempt to monopolize the herd of aphids which 

 they attend, but seem to admit the equal claim of other species 

 of ants. When a dead insect is found by them, a number of 

 workers gather around it and suck out its fluids, which they then 

 carry to the nest, leaving the dry, chitinous skeleton behind. I 

 have noticed, however, that they nearly always carry the hard 

 chitinous head of an insect into the nest, and I have often won- 

 dered why this is done. In the actions of ants living in my 

 artificial nests I think that I have found explanation. After feed- 

 ing these colonies a number of white grubs, I have noticed that 

 the head is always carried from the feeding-room into the nest. 

 Here it remains for a few days, and then the empty shell, which 

 has been divested of the last particle of soft tissue, is thrown 

 upon the rubbish heap. It may be that in the head is a choice 

 bit of food, possibly the brain of the larva, which is served 

 directly to some special member of the household, or it may be 



