370 APPLIED ENTOMOLOGY 



light that she hastens to conceal herself on the slightest disturbance to the nest. 

 She soon becomes utterly indifferent to her progeny, leaving them entirely to 

 the care of the workers, while she limits her activities to laying eggs and imbibing 

 liquid food from the tongues of her attendants. This copious nourishment 

 restores her depleted fat-body, but her disappearing wing-muscles have left her 

 thoracic cavity hollow and filled with air which causes her to float when placed 

 in water. With this circumscribed activity, she lives on, sometimes to an age of 

 15 years, as a mere egg-laying machine" (Wheeler). 



Of course there are many fatalities in such a history as this. Birds, 

 dryness in their burrows, excessive moisture or cold, underground insects 

 attacking them, together destroy the great majority of these ants just 

 starting new colonies. Then too, the amount of nourishment stored in 

 the individual is an important factor, some species having so little that 

 they are wholly unable to start new colonies. An individual of such a 

 species therefore either joins a colony already established, a queenless 

 colony of a related species if she can induce the colony to accept her, or 

 she may enter a colony of a very different species and, killing its members, 

 raise their young until they emerge when they will accept her as their 

 queen. Rarely two queens may start a colony together. 



After the colony is well under way the queen limits her duties to egg 

 laying, and may live many years. In one case a queen lived nearly 

 15 years in confinement and may have been older! This is the greatest 

 age known to have been attained by any adult insect. The males die 

 soon after mating. 



The relation of ants to plant lice is most interesting and has already 

 been referred to (pp. 197 and 203). It does not exist with all species 

 of ants but in at least a large number honey-dew is an important part 

 of their diet and in some cases it may be their only food. There is every 

 evidence that the benefit is mutual, the ants protecting the aphids, driv- 

 ing away the enemies of these insects or carrying the aphids to protected 

 places. Ants that care for root-feeding aphids keep them in chambers or 

 galleries, conduct them to their sources of food supply, collect and store 

 their eggs for the winter, and in spring take the young to their food. 



The Corn-root Aphis so injurious to corn, as already described, is 

 thus cared for by ants. Scale insects which produce honey-dew are also 

 cared for in a sense, for ants are very attentive to them and to quite an 

 extent prevent the attacks of the enemies of the scales by their presence 

 and activities. Thus in an indirect way the protection by ants of 

 plant lice, scale insects, white flies, leaf hoppers, and in fact any insects 

 which produce honey-dew, establishes such ants as injurious. 



Some kinds of ants have most remarkable habits worthy of a brief 

 reference here. Some species may make raids on the nests of other 

 kinds, and carry off their worker larvae and pupae to their own nests, 

 where many probably serve as food but a few may be reared and become, 



