Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER II. The Sexes, And Criticism Of Sexual Selection. § i. To gain a firmer and broader foundation on which to base a theory of the differences between the sexes, it is necessary to take another review of the facts of the case. Instead of considering the differences as they are expressed in the successive classes of animals, it will be more convenient to arrange them for themselves, according as they affect habit, size, length of life, and the like. The review must again be merely representative, without any attempt at completeness. Male and Female Coccus Insects, a, part of a cactus plant with the excrescences due to coccus insects; b, male ; c, female. § 2. General Habit.—Let us begin with an extreme yet well-known case. The female cochineal insect, laden with reserve products in the form of the well-known pigment, spendsmuch 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 tw...