232 THE EVOLUTION THEORY 



a, faint idea of them without entering on a long catalogue ; whoever 

 wishes a complete survey has only to consult Darwin's Descent of 

 Man. 



But the significance of sexual selection is by no means exhausted 

 with the production of the male sexual characters, for these characters 

 are often more or less completely transferred to the females, and thus 

 give rise to a transformation of the whole species, and not only of the 

 male section of it. This is obviously a very important consequence of 

 sexual selection, one which, as we shall see, materially deepens our 

 insight into the mode of origin of new species. 



First let us try to determine the facts. Many male characters are 

 not represented in the female in any degree, and therefore have never 

 been transmitted to them at all. Such are the mane of the lion, the 

 grasping antennae of Moina, the turban eyes of the Ephemerides, the 

 intensification of the sense of smell in Leptodora, the lasso-like antennse 

 of the Copepods, the scent-scales of the butterflies, and the musk glands 

 of the alligators and stags. But in other cases there has been 

 transmission, though only to a slight extent. Thus many female 

 humming-birds have a faint indication of the magnificent metallic 

 colouring of the males ; many female blue butterflies have a tinge 

 of the beautiful blue of their mates ; the females of the stag-beetle 

 (Lucanus cervus) possess a diminutive suggestion of the antler-like 

 jaws of the male, and the female crickets, although they do not chirp, 

 have a slight indication of the ' musical ' mechanism of the male on 

 the wing-coverts, and some of them even produce feeble notes at 

 certain times. 



It can be proved, however, that such transmissions may, in the 

 course of many successive generations, become intensified until the 

 characters are exhibited by the females in the same degree as in the 

 males. I know no better example of this than that afforded by the 

 beautiful buttei-flies of the genus Lyccuna. In this genus, which is 

 rich in species and widely distributed over the whole earth, and 

 must therefore be an old one, the upper surface of the wing is blue in 

 by far the greater number of species, at least in the male sex. But 

 there are three or four species which are dark-brown, and quite 

 or nearly alike in the two sexes ; such are the species ij/ccuwa aged is, 

 L. eumedon, L. admetus, and others. Everything indicates that this 

 is the primitive colour of the genus. Moreover, there are some species 

 with brown females, in which the males are not completely blue, 

 but which have a slight bluish tinge, like L. al&us, the smallest of our 

 indigenous Blues. Then follows a host of beautiful species, like 

 L. ulexis, L. adonis, L. damon, L. corydon, and many others, with 



