186 Dynamic TJieory. 



the reduction of the reproductive organs, and of the eggs, the sluggish 

 parturition, the absence of mating, the rapid growth of the young, and, 

 in general, the development of individualistic and egoistic qualities, and 

 the suppression of the altruistic, the breaking up of the family and the 

 loosening of all the bonds of the society. 



The parasitic Bees mentioned by Darwin (Sel. of species, 194) are 

 another example. There are many varieties of them that deposit their 

 eggs in the nests of other Bees, and they thus escape the work of col- 

 lecting pollen to store the nests. But in shirking out of this work they 

 have not only lost the art of performing it but have even lost the appa- 

 ratus necessary to do it, and must depend on other bees to rear their 

 young. 



The history of the slave-making ants, related by Cuvier and Darwin, 

 is to the same effect. Some of the tribes are fierce and enterprising, 

 making long journe3 r s to the nests of others to carry off their pupae. 

 These they rear in their own nests to become their household servants, 

 where they are compelled to build and arrange the nest and care for the 

 young. In other cases the slaves are likewise field servants and sol- 

 diers and assist their masters in defending the nest or in cariying the 

 larvae and pupae out of danger. But the most extreme case is that of 

 the Formica Polyergcs rufescens. Ants generally are divided into three 

 sexes masculine, feminine and neuter. The neuters, like the workers 

 among the bees, are females with undeveloped and functionless ovaries. 

 And these neuters, in some varieties, do all the work, the males and 

 females doing nothing after the eggs are laid. Cuvier even says the 

 neuters drive out the others in some cases. But in the tribe above 

 mentioned, in which the males and females have shirked out of all work 

 and even forgotten how to do it, the neuters, too, have adopted shiftless 

 habits ; for, having taken up the practice, of making slaves, they have 

 put all the work upon them. The neuters are very fierce and enterpris- 

 ing in capturing the larvae and pupae of the Formica fusca, which they 

 rear in their nests into neuter slaves. But they do nothing else what- 

 ever. These slaves not only build and open and close the nests, but 

 they feed their masters, both old young, who would all starve to death 

 before they would feed themselves. 



To observe the extreme effects of parasitism, we must go to such ani- 

 mals as the Sacculina and the Entoconcha mirabilis. The sacculina is 

 a crustacean parasite on a brother crustacean, the Hermit Crab. The 

 young sacculina is hatched from an egg, and is an oval body possessing 

 three pairs of legs and usually a single eye in the middle of the head, 

 but no mouth or digestive system. It is able by means of its limbs to 

 swim. The animal in this stage is called a nauplius, and it closely 

 resembles the nauplius of those other curious crustaceans, the Barnacles 



