INTROtoUOTlONi 



Other patterns. Amongst moths, however, cases of " sexual selection " 

 must be very rare, although the observations of Dr. Chapman and Mr. 

 Robson, go far to suggest that the female of Hepialus humuli positively 

 selects a male which is either conspicuously large or white. However, I 

 do not believe that "sexual selection " is so widely or extensively carried 

 on by female lepidoptera as has been generally supposed. Certainly 

 in those lepidoptera which have come under my notice it is not so. I 

 have repeatedly observed that females, as soon as they have emerged 

 from the pupa, and before their wings have become fully developed, 

 have paired with the first male that has offered itself, the sexual 

 attraction having overcome all sexual preference, which could hardly 

 exist in females just emerged and with their wings undeveloped. One 

 finds wherever any species abounds, as in the various Lyccence, wretched 

 little males in copulation with large well-developed females and vice 

 versa, whilst dozens of well-developed specimens are everywhere 

 around. In fact, the ordinary quiescent condition of the female com- 

 pared with the male at this time, leads one rather to suppose that the 

 female is generally quite a passive agent in the matter, although I am 

 quite ready to grant that when attractive-looking males do pair with 

 well-developed females, heredity will stamp the characters of such a 

 male and female on the offspring. I quite agree too, with Geddes and 

 Thomson, when they write that if " a casual variation, advantageous 

 to its possessor (usually a male) in courtship and reproduction becomes 

 established and perfected by the success it entails," then " * sexual 

 selection ' is only a special case of the more general process of 

 ' natural selection,' with this difference, that the female for the most 

 part takes the place of the picking and choosing which is supposed to 

 work out the perfection of the species." Whilst Darwin thinks the 

 beauty of male insects &c., is due to selection on the part of the female, 

 Wallace considers that the sober colours of female insects are due to 

 " natural selection " and have been the means of their preservation, 

 since it (" natural selection ") has eliminated those individuals of the 

 latter sex that are most gay by making them conspicuous to their 

 enemies. In other words, as Geddes and Thomson put it: "Darwin 

 starts from inconspicuous forms, and derives gorgeous males by 

 " sexual selection ; " Wallace starts from conspicuous forms, and derives 

 the sober females by " natural selection ; " the former trusts to the 

 preservation of beauty, the latter to its extinction." I cannot certainly 

 bring myself to believe in the ability of the female to carry out 

 " sexual selection " to the extent assumed by Darwin. At the same time 

 I believe to the fullest in " natural selection ; " and really the study 

 of at least some of our lepidoptera is greatly in support of Wallace's 

 view of it. No group of our butterflies exhibit more marked characters 

 than the Lyccenidce. In those species where both sexes are alike, both 

 are generally brilliantly coloured, as in our common Polyommatus 

 phlceas ; in those species where the sexes are permanently different 

 (dimorphic), the female is of the duller colour ; but in those species in 

 which there is a transition state, the male is the constant, the female 

 the inconstant element, as in Lyccena corydon. In this species, the 

 male is always blue (or in southern countries approaching white), 

 whilst the female varies in tint, from a brilliancy almost equal to the 

 male to a dull sooty-black with no trace of blue in it, and tkis is the 



