ANIMAL SOCIETIES — SNODGRASS 429 



Here is the first case below the insects in wliich we fuid a colony of 

 free individuals with a common home. There is, however, no differen- 

 tiation of the colony members into castes as with the insects. 



THE SOCIAL INSECTS 



The insects are noted for their diversity of habits and ways of liv- 

 ing. It is not surprising therefore that some of them have adopted 

 the social way of life. W. M. Wheeler (192e3) lists 21 families and 3 

 orders of insects containing species that are social in some degree. 

 The social insects of particular interest, however, are the termites, the 

 ants, and certain species of the wasps and bees. Mention should be 

 made also of the webworms and tent caterpillars, which make those 

 large silken domiciles seen in trees. These are juvenile societies, the 

 members of which hatch from a single batch of eggs, and all cooperate 

 in making the tent. Evidently they are activated by a common in- 

 stinct. They do not revert to individuality until the time for pupa- 

 tion, when they leave the nest separately and each seeks a place for 

 spinning its cocoon in solitude. 



The fundamental principle on which the best organized insect 

 societies are based is the restriction of the reproductive f miction to one 

 fertilized female, known entomologically as the queen. Though the 

 ants do not always enforce this rule, the supernumerary queens are 

 daughters of the primary queen. A single maternity assures uni- 

 formity in the members of the society so long as the queen has the 

 proper hereditary units, or genes. Furthermore, the progeny of the 

 queen, except individuals that are destined to perpetuate the species, 

 is sterilized. The sterile forms thus cannot rear families of their 

 own and create confusion. They are destined to be workers, or in 

 some cases soldiers, and are endowed with instincts that tell them what 

 they are supposed to do and how to do it. The workers can still learn 

 a few things when necessary, but they caimot assert independence of 

 action; all their work must be coordinated for the good of the society. 

 There can be no willful deviation from an instinct. 



The insect society is thus not a crowd of associated free individuals. 

 It is a thoroughly organized social system. The queen is the mother 

 of the colony, and her principal physical function is egg laying. How- 

 ever, she is also an autocratic ruler of her progeny, though she gives 

 her orders in the form of transmitted instincts. The differentiation 

 of structure and duties among the members of the insect society re- 

 sults in the caste system, but the insect castes have no relation to the 

 "pecking order" of the barnyard, or to the castes of human societies. 

 The workers are dominant in the insect society. Owing to the auto- 

 matic suppression of indi^ddual freedom, insect societies have little 

 internal trouble or dissension, and no such thing as a criminal ele- 



