MUTUAL AID AND COMMUNAL LIFE .\.\lONG ANLMALS 395 



which are wingless, wingless workers of both sexes not capaljle 

 of reproduction, and wingless soldiers of both sexes also in- 

 capable of reproduction. The production of new in(hvi(hials 

 is the sole business of the fertile males and females; the workers 

 build the nest and collect food, and the soldiers i)rotect the 

 connuunity from the attacks of marauding insects. The egg- 

 laying queen grows to monstrous size in some species, being some- 

 times four or five inches long, while the other individuals of the 

 community are not 

 more than half or 

 three-quarters of an 

 inch long. The great 

 size of the queen is 

 due to the enormous 

 number of eggs in 

 her body. 



We have pointed 

 out elsewhere that 

 the complexity of 

 the bodies of the 

 higher animals de- 

 pends on a specirli- 

 zation or different ir.- 

 tion of parts, due 

 to the assumption of 

 different functions or 

 duties by different 



parts of the body; that the degree of structural differentiation 

 depends on the degree or extent of division of labor shown in 

 the economy of the animr.l. It is obvious that the same jirin- 

 ciple of division of \v.hor with accomi)anying modihcation of 

 structure is the basis of colonial and conununal life. It is 

 simply a manifestation of the princii)le among individuals in- 

 stead"^of among organs. Tlie division of the necessary labois 

 of life among the different zooids of the colonial jellyfisli is 

 plainlv the reason for the profound and striking.- but always 

 reasonable and ex])lical)le, modihcations of the typical iH>lyp 

 or medusa IkkIv, wliich is shown by the swinuning zooids, the 

 feeding zooids, the sense zooids, and the others of the colony. 

 And similarlv in the case of the termite community, the sol- 

 dier individuals are difTerent structurally from the worker i-- 



FiG. 247. — Termites: a, Queen; b, male; c, worker; 



d. soltliiT. 



