THE SEXES, AND CRITICISM OF SEXUAL SELECTION. I 7 



much of its life like a mere quiescent gall on the cactus plant. 

 The male, on the other hand, in his adult state is agile, 

 restless, and short-lived. Now this is no mere curiosity of the 

 entomologist, but in reality a vivid emblem of what is an aver- 

 age truth throughout the world of animals — the preponderating 

 passivity of the females, the predominant activity of the males. 

 These coccus insects are the martyrs of their respective sexes. 

 Take another illustration, again somewhat extreme. There is 

 a troublesome threadworm {^Heterodcra schachtii) infesting the 

 turnip plant, which parallels in more ways than one the contrast 

 of the coccus insects. The adult male is agile, and like many 

 another threadworm ; the adult female, however, is quiescent, 

 and bloated like a drawn-out lemon. It may be asked, how- 

 ever, is not this merely the natural nemesis 

 of parasitism? The life-history answers 

 this objection. The two sexes are at first 

 alike, — agile, and resembling most thread- 

 worms ; they become parasitic, and lose 

 both activity and nematode form ; but the 

 interesting fact is further, that the male 

 recovers himself, while the female remains a 

 victim. In other insect and worm types 

 the same story, in less accented characters, 

 may be distinctly read. In many crusta- 

 ceans, again, the femalesonly are parasitic; 

 and while this is in part explained by their 

 habit of seeking shelter for egg-laying pur- 

 poses, it also expresses the constitutional 

 bias of the sex. The insect order of bee 

 parasites {Strepsipterd) is remarkable for the 

 completely passive and even larval character 

 of the blind parasitic females, while the 

 adult males are free, winged, and short-lived. 



Throughout the class of insects there are Female Clwndracanthus, a 

 •11 i^ i ■ r ii „„n ^.,^^ parasitic Crustacean, 



numerous illustrations oi the excellence ^^^h pigmy male («) 

 of the males over the females, alike in attached^just above the 



origin of the long egg- 



muscular power and sensory acuteness. sacs {b) of the female. 

 The diverse series of efforts by which the -^''^'^ <^'^"^- 

 males of so many different animals, from cicadas to birds, 

 sustain the love-chorus, affords another set of illustrations of 

 pre-eminent masculine activity. 



Without multiplying instances, a review of the animal 



B 



