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occurs in several species of the dragon flies of the genus Agrion, in which a certain number of females are of an orange color, and thus differ from the males and ordinary females.
He suggests that this is probably a case of reversion, for in the true Libellulae, whenever the sexes differ in color, the females are always orange or yellow, so that, supposing Agrion to be descended from some primordial form having the characteristic sexual colors of the typical Libellulae, it would not be surprising that a tendency to vary in this manner should occur in the females alone.
This explanation seems to apply to several of the recorded cases of female polymorphism, but not to all, and we must acknowledge that in these cases the female 6hows, in a far greater degree than the male, a tendency to deviate from the primitive form of the species, and to give rise to new race modifications.
We have already called attention to the fact that among the Crustacea there are many cases of male polymorphism, and many cases of the same kind are known among male insects; as well as many cases, besides those I have mentioned, of female polymorphism.
In many of the social insects we have most profound structural modifications, and most complex instincts, which can only have arisen in females; and as allied species of social insects differ from each other in characters which are confined to the females, we must acknowledge that in these forms there is no lack on the part of this sex of a power to give rise to hereditary race modifications.
That facts of this kind present a serious difficulty 1 cannot deny, but we must recollect thx.t our hypothesis does not demand that the power to transmit variations should be confined exclusively to males, but simply that it should be much more active in them than it is in the females, and we certainly find that this is the case. I believe that we may, in justice, conclude that, with greater knowledge of the few cases where females give evidence that they have this power to an exceptional degree, the difficulty will disappear, for they are certainly deviations from a general rule, and they must therefore be regarded as special cases, to be studied by themselves. It is interesting to notice that both parthenogenesis and female race-modification are more frequent among the Anthropods than in most other groups of animals, and that parthenogenesis is known to occur in the Lepidoptera and in the 'social insects, two of the groups where great modifications can be most clearly traced to a female origin. It is not improbable that the power of the egg to develop without fertilization, and its power to store up and transmit gemmules, maybe related in some way, so that when the one power is acquired the other is also.
Every one is aware that we meet, in the most diverse groups of animals, with structures and instincts which are confined to the females; such as the brood-chambers of Daphnia, the ovipositor of the ichneumon fly, the sting of the honey bee, the marsupial pouch of the oppossum, the nest-building and incubating instincts of birds, or the nursing habit of female mammals. Wc must bear in mind, however, that in many of these cases a male origin for the successive variations is not out of the question. The fact that the male Hippocampus and not the female has an incubatory pouch, and that mammae are present in most male mammals, certainly shows the possibility of a male origin for these structures, and as many male birds either share in the work of nest-building and incubating or aid the female in this duty, there is certainly no difficulty in believing that these instincts have had a male origin.
The remarkable instinct which leads some species of cuckoo and crow blackbirds to lay their eggs in the nests of other species, must have originated in females, and a collection of all the cases which must be explained in the same way would make a formidable list, but the fact would still remain true, that among animals with separate sexes, male modifications are very much more frequent than female modifications, and this is all that our theory requires.
THE EVIDENCE FROM THE INTELLECTUAL DIFFERENCES BETWEEN MEN AND WOMEN.
(This chapter, 'which was published in the Popular Science Monthly for June and July, 1879, under the title, "The Condition of Women from a Zoological Point of View," is reprinted here, almost without change.)
Zoology is the scientific study of the past history of animal life, for the purpose of understanding its future history. Since man has, in part at least, conscious control of his own destiny, it is of vital importance to human welfare in the future that we should learn, by this comparative study of the past, what are the lines along which progress is to be expected, and what the conditions favorable to this progress, in order that we may use our exceptional powers in harmony with the order of nature.
The study of the growth of civilization shows that human advancement has been accompanied by slow but constant improvement in the condition of women, as compared with men, and that it may be very accurately measured by this standard. Judging from the past, we may be sure that one of the paths for the future progress of the race lies in this improvement, and the position of women must therefore be regarded as a most important social problem. If there is, as I shall try to show, a fundamental and constantly increasing difference between the sexes; if their needs are different, and if their parts in the intellectual, moral, and social evolution of the race are, like their parts in the reproductive process, complemental, the clear recognition of this difference must form both the foundation and superstructure of all plans for the improvement of women.
If there is this fundamental difference in the sociological influence of the sexes, its origin must be sought in the physiological differences between them, although the subject is now very far removed from the province of ordinary physiology. While we fully recognize the insignificance of the merely animal differences between the sexes, as compared with their intellectual and moral influence, it is none the less true that the origin of the latter is to be found in the former; in the same manner —to use a humble illustration—that the origin of the self-denying, disinterested devotion of a dog to his master is to be found in that self-negation which is necessary in order that a herd of wolves may act in concert under a leader, for the general good.
In order to trace the origin and significance of the differences which attain to such complexity and importance in the human race, we must carry our retrospect back far beyond the beginning of civilization, and trace the growth and meaning of sex in the lower forms of life. In so doing I shall ask attention to several propositions which may not at first appear to have any bearing upon our subject, or any very close relation to each other. I shall then try to show what this relation is, and point out its bearing upon the education of women.
Every organism which is born from an egg or seed is a resultant of the two systems of laws or conditions which may be spoken of abstractly as the law of heredity and the law of variation, or, to use the old teleological terms, each organism is a mean between the principle of adhe