HYMENOPTERA 179 



Although ants are general feeders upon animal substances and fruit 

 juices, they are very fond of sweet substances like the " honey-dew " 

 given off by aphids when stroked by the ants' antennas. In return for 

 this choice food the ants shelter the aphid eggs in their nests through the 

 winter and carry the young plant-lice to tender plants in the spring. When 

 for any cause these plants become unsafe or unfit for the food of the aphids, 

 the ants will carry them to other plants. If ants are seen running up and 

 down the stem of some favorite plant, one may know, unless there is a 

 sweet substance exuding from bark or flower, that they are " pasturing their 

 cows " upon the juices of tender shoots and newly forming buds. A little 

 close looking will reveal myriads of tiny plant-lice on the under side or in 

 the axles of the leaves. Spraying with a little dilute commercial nicotin 

 will rid the plants of both ants and plant-lice. Arsenic poisons cannot 

 affect aphids or other insects having sucking mouth parts, since their food 

 consists of the internal juices of plants which cannot be reached by the 

 poison. 



There are many other insects which live in the nests of ants. In 1900 

 Wasmann recorded 1177 insects living in the nests of ants (myrmecoph- 

 ilous insects), many of which were beetles. Most of these insects live 

 a commensal life with the ants. It is not known of what advantage they 

 are to their hosts. The guests, however, obtain shelter, food, moderate 

 temperature, defense against enemies, and even, in the case of migratory 

 ants, transportation. In the case of some small beetles, however, there is 

 true symbiosis with the ants, the beetles secreting a sweet substance which 

 the ants eat greedily, and in return the ants "clean, care for, and feed by 

 regurgitation" the degenerate little beetles. 



The ants furnish an example of a perfect communistic society. There is 

 no special care or favoritism for wife or child or friend, but a common love 

 for the whole community. "Everything is done for the good of the whole 

 and nothing for the individual. The state makes wars, provides food for 

 all, cares for the children, owns all the property, the fate of each one is 

 determined by, the accident of birth, and each takes up its work without a 

 murmur. . . . This perfect commune has developed courage, patriotism, 

 loyalty, and never-failing industry, but also war, pillage, slavery, and an 

 utter disregard of the rights of other communities and individuals."' 



Most of the ants which have been described in this country can be placed 

 in one of three families: (1) Formic'idse, in which is found the interesting 

 carpenter ant (Cam-pon'otus pennsylva'nicics) , one of the largest of our com- 

 mon black ants. It builds its nest in the dead interior wood of living trees 

 and wooden buildings. Here also is the mound-building ant {For'mica ex- 

 sectoi'des), with its rust-red head and thorax and black abdomen and legs. 

 Its ant-hills are from 5 to 10 feet in diameter. One of the most interest- 

 ing of the family is the slave-making ant {For'mica diffic'ilis) . In this species 

 the workers work with the slaves, but Polyer'gus rujes'cens, a European 

 species, depends upon the slaves to do all the work for the community. 

 The adults are not taken captive, but in war and pillaging the larvae and 

 pupse are some of them eaten and some of them carried home, where, if not 

 eaten, they develop into the adult workers, and instinctively go to work for 

 their hosts, building nests, bringing food, and nursing the young. In some 

 species this is carried on to such an extent that the hosts become unfitted for 

 any work but that of warfare, and are dependent solely upon the slaves for 

 shelter, food, and all the necessary work of the community. Thus their 



' Comstock, p. 634. 



