THE SEXES, AND CRITICISM OF SEXUAL SELECTION. 



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 \Heterodera 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 {Sfrepsiptera) 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 

 numerous illustrations of the excellence 

 of the males over the females, alike in 

 muscular power and sensory acuteness. 

 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 



Female Chondracaftthus, a 

 parasitic Crustacean, 

 with pigmy male {a) 

 attached just above the 

 origin of the long egg- 

 sacs {b) of the female. 

 — From Claus. 



