The whole question of sex-parasitism as it appears in these first pages of the life-histories of sexes is one of deep suggestion; and one, moreover, that casts forward sharp side-lights on modern sex problems. In some early forms, where the conditions of life are similar for the two sexes, the male and the female are often like one another. Thus it is very difficult to distinguish a male starfish from a female starfish, or a male sea-urchin from a female sea-urchin. It becomes abundantly clear that degeneration in active function, whether it be that of the male or the female, is the inevitable nemesis of parasitism. The males and females in the cases we have examined may be said to be martyrs to their respective sexes.
A further truth of the utmost importance becomes manifest. Many differences between the relative position of the sexes, which we are apt to suppose are inherent in the female or male, are not inherent, in light of these early and varying types. We see that the sex-relationship and the character of the female and male assume different forms, changing as the conditions of life vary. Again and again when we come to examine the position of women in different periods of civilisation, we shall find that whenever the conditions of life have tended to withdraw them from the social activities of labour, restricting them, like these early sex-victims, to the passive exercise of their reproductive functions alone, that such parasitism has resulted invariably in the degeneration of woman, and through her passing on such deterioration to her sons, there has followed, after a longer or shorter period, the degeneration of society. But these questions belong to the later part of our inquiry, and cannot be entered on here. Yet it were well to fix in our minds at once the dangers, without escape, that follow sex-parasitism.
It may be thought that these cases of sex-victims are exceptions, and that, therefore, it is unsafe to draw conclusions from them. The truth would rather seem to be that they are extreme examples of conditions that were common at one stage of life. There is no doubt that up to the level of the amphibians female superiority in size, and often in power of function, prevails.[28] If, for example, we look at insects generally, the males are smaller than the females, especially in the imago state. There are many species, belonging to different orders—as, for instance, certain moths and butterflies—in which this superiority is very marked. The males are either not provided with any functional organs for eating, or have these imperfectly developed. It seems evident that their sole function is to fertilise the female. A familiar and interesting example is furnished by the common mosquitoes, among whom the female alone, with its harmful sting, is known to the unscientific world. The males, frail and weaponless little creatures, swarm with the females in the early summer, and then pass away, their work being done.
Dr. Howard, writing of the mosquito in America, says—
"It is a well-known fact that the adult male mosquito does not necessarily take nourishment, and that the adult female does not necessarily rely on the blood of warm-blooded animals. The mouth parts of the male are so different from those of the female that it is probable that, if it feeds at all, it obtains its food in quite a different manner from the female. They are often observed sipping at drops of water, and in one instance a fondness for molasses has been recorded."[29]
We find many examples of such structural modifications acquired for the purpose of adapting the sexes to different modes of life. Darwin notes that the females of certain flies are blood-suckers, whilst the males, living on flowers, have mouths destitute of mandibles.[30] The females are carnivorous, the males herbivorous. It would be easy to bring forward many further examples among the invertebrates in which the differences between the sexes indicates very clearly the persistence of female superiority. But for these I must refer the reader to the works of Darwin and other entomologists, and to the many interesting cases given by Professor Lester Ward. There are, it is true, exceptions, but these may be explained by the conditions under which the species live.
Even when we ascend the scale to back-boned animals, cases are not wanting in which the early superiority in size of the female remains unaltered. The smallest known vertebrate, Heterandria formosa, has females very considerably larger than the males.[31] Among fishes the males are commonly smaller than the females, who are also, as a rule, considerably more numerous.[32] This is a fact that fishermen are well aware of. I may mention, as an example, that on one occasion when my husband and I caught twenty-five trout in a mountain lake in Wales there were only two males among them. It is curious to find that any care of offspring that is evident among fishes is usually paternal. This furnishes another instance of the truth so necessary to learn that the sex-relationships may assume almost any form to suit the varying conditions of life.
There are some mammals among whom the sexes do not differ appreciably in size and strength, and very little or not at all, in coloration and ornament. Such is the case with nearly all the great family of rodents. It is also the case with the Erinaceidæ, or at least with its typical sub-family of hedgehogs.[33] Even among birds, where the sex instincts have attained to their highest and most æsthetic expression, we find some large families—as, for example, the hawks—in which the female is usually the larger and finer bird.[34] Thus the adult male of the common sparrow-hawk is much smaller than the female, the length of the male being 13 ins., wing 7.7 ins., and that of the female 15.4 ins., wing 9 ins. The male peregrine, known to hawkers as the tiercel, is greatly inferior in size to his mate. The merlin, the osprey, the falcon, the spotted eagle, the golden eagle, the gos-hawk, the harrier, the buzzard, the eagle-owl, and other species of owls are further examples where the female bird is larger than the male. Among many of these families the female birds very closely resemble the males, and where differences in colour and ornament do occur, they are slight.
A further point of the greatest importance to us requires to be made. Wherever amongst the birds the sexes are alike the habits of their lives are also alike. The female as well as the male obtains food, the nest is built together, and the young are cared for by both parents. These beautiful examples of sex equality among the birds cannot be regarded as exceptions that have arisen by chance—a reversal of the usual rule of the sexes; rather they show the persistence of the earlier relations between the female and the male carried to a finer development under conditions of life favourable to the female. I will not here say more upon this subject, as I shall have to refer to it in greater detail when we come to consider the sexual and familial habits of birds. I will only add that in their delicacy and devotion to each other and to their offspring, birds in their unions have advanced to a much further stage than we have in our marriages. These associations of our ancestral lovers claim our attentive study.