DIFFERENTIATION OF INDIVIDUALS AND ADAPTATION 1 23 



usually associated with the instinct of home building, and thus 

 a high degree of division of labor with its great advantages 

 becomes possible. This is carried to such an extent that often 

 polymorphic individuals, such as queens, drones and workers, 

 result, much as in the organic colonies. In such cases it is clear 

 that the individual life comes to be bound up in the success of 

 the community. Such forms usually exert great care for their 

 young and develop a relatively high order of "intelligence." 

 The principal social forms are the ants, of which there are more 

 than twa thousand species; some of the bees and wasps; the 

 termites, or so-called white-ants; beavers; some monkeys and 

 man. 



155. Library Exercise. — Make a report on the social life of the honey-bee, 

 including the following points: the home; the kinds of individuals, their origin, 

 and their work in the community; their food and its preparation; mode of caring 

 for the young; swarming and its significance. Make a similar report concerning 

 some species of ant. Find facts concerning the following topics: "ants' cows;" 

 slave-making among the ants; army ants; the agricultural ant. 



157. Competition among animals of the same species is not, 

 for the most part, of a personal character except in the case of 

 the struggles of the males of polygamous animals. The ordinary 

 struggle for existence among them is merely that of food-seeking, 

 where all possess the same organs and habits but in varying 

 degrees of excellence. Those which have the greater strength, 

 hardiness, or intelligence are more likely to get their portion of 

 food at the expense of the weaker, and thus to propagate their 

 qualities. Sometimes, however, animals live directly at the ex- 

 pense of their own species. Young spiders before escaping from 

 the cocoon in which they are hatched devour each other, thus 

 instituting an afcute phase of the struggle for existence in the 

 place of the protection prepared by parental care. Many fishes 

 are known to devour their own young. We have all had occa- 

 sion to wonder what becomes of the small frogs in a box contain- 

 ing large ones. 



The struggle between the males for the possession of the 

 females has resulted in the development of many interesting 

 adaptations. The struggle may take the form of actual combat 



