192 THE COURTSHIP OF ANIMALS 



Selection theory have been dazzled by the tinsel, and 

 have missed the essential elements — the physical and 

 psychological side of the display — the contortions, 

 prancings, and so on, and they have missed the even 

 more important element, the preliminary struggle for 

 territory. 



In this new light, the gaily-bedizened individuals of the 

 Insect world may be surveyed afresh. The explanation of 

 such of their features as are commonly attributed to 

 Sexual Selection in terms of female choice, whereby only 

 the most favoured from among a crowd of suitors could 

 hope to succeed, may now be replaced by that which 

 obtains also in the case of the higher animals. It seems 

 to fit the facts better. One cannot understand, for 

 example, how, on the interpretation of Sexual Selection, 

 the extraordinary disparity in numbers between the 

 sexes of some species of Butterflies came about. Thus in 

 that marvellously beautiful genus Ornithoptera there is 

 one species (0. brookiand) in which the females are 

 excessively rare ; so much so that the collector Kunstler 

 could only obtain fifteen females to one thousand males. 

 Though the males, among the Butterflies, are commonly 

 much more numerous than the females, the disparity is 

 rarely so great as with this species ; but there are many 

 in which the proportion of males to females is as fifty 

 to one. As with the higher vertebrates selection affords 

 no explanation of this curious disproportion. Though 

 according to Weismann it fulfills " the first postulate in 

 * Sexual Selection,' namely, that there be an unequal 

 number of individuals in the two sexes." But Sexual 

 Selection here has a little over-reached itself, for surely 

 one hundred suitors seems an embarrassing number for 

 an inexperienced female to have to choose from ! To say 



