DIFFICULTIES OF INDUCTIVE VERIFICATION. 417 



Incubation, and the young afterwards. Evidently all these 

 differences affect the proportion between the total cost of re- 

 production and the total cost of individuation. 



Whether the species is monogamous or polygamous, and 

 whether there are marked differences of size or of structure 

 between males and females, are also questions not to be over- 

 looked. If there are many females to one male, the total 

 quantity of assimilated matter devoted by each generation to 

 the production of a new generation, is greater than if there 

 is a male to each female. Similarly, where the requirements 

 are such that small males will suffice, the larger quantity of 

 food left for the females, makes possible a greater surplus 

 available for reproduction. And where, as in some of the 

 Cirrhipedia, or such a parasite as Sphcerularia fiojiibi, the 

 female is a thousand or many thousand times the size of the 

 male, the reproductive capacity is almost doubled : the effect 

 on the rate of multiplication being something like that which 

 would result if any ordinary race could have all its males 

 replaced by fertile females. Conversely, where the 



habits of the race render it needless that both sexes should 

 have developed powers of locomotion — where, as in the Glow- 

 worm and sundry Lcpidoptera, the female is wingless while 

 the male has wings — the cost of Individuation not being so 

 great for the species as a whole, there arises a greater reserve 

 for Genesis : the matter which would otherwise have gone to 

 the production of wings and the using of them, may go to 

 the production of ova. 



Other complications, as those which we see in Bees and 

 Ants, might be dwelt on ; but the foregoing will amply serve 

 the intended purpose. 



§ 333. To ascertain by comparison of cases whether Indi- 

 viduation and Genesis vary inversely, is thus an under- 

 taking so beset with difficulties, that we might despair of any 

 satisfactory results, were not the relation too marked a one 

 to be hidden even by all these complexities. Species are 



