INSECT COMMUNITIES 293 



a humble-bees' nest. In this case, however, the welfare 

 of the young must be the sole incentive, for there is no 

 store of honey to pilfer. 



The social habits of ants are even more complex and 

 remarkable than those of bees and wasps. Moreover, 

 while the communities of some species are less perfectly 

 organised than others, solitary ants are unknown. Yet 

 ants, as a family, do not excel in architecture. They 

 have no specialised building material such as wax or papier- 

 mache. Some species dwell in subterranean chambers or 

 burrow into decaying tree stumps ; others, as we have 

 already seen, frequent the internodes or interstices of 

 living plants ; while a few take up their abode in the walls 

 of larger ants' nests, and (like mice in our houses) live by 

 filching the stores of their hosts. 



In this country the most pretentious nests are made 

 by the large species of the genus Formica, of which the 

 common red wood-ant or "horse-ant" (F. rufa) is the 

 best known example. It is especially characteristic of fir 

 woods, where it piles up mounds of pine needles and 

 small twigs, these accumulations surmounting a labyrinth 

 of galleries and chambers which extends far into the 

 ground. A wood - ant community usually comprises 

 several egg-laying females, or queens, and many thousands 

 of workers. The latter vary greatly in size ; and, as with 

 humble-bees, the larger individuals engage in foraging 

 expeditions, and collect building materials, while the 

 smaller act as nurses, and seldom leave the nest. Winged 

 males and young queens are only found in the nest as the 

 season of swarming approaches. 



Among ants in general the caste-system is carried 

 to extraordinary lengths. In some instances the males 

 and females of the same species exhibit remarkable 

 differences — some being winged and others wingless ; 



