724 The Zoologist — May, 1867. 



Until his objects are chloroformed and carded the coleopterist has no 

 knowledge of them whatever; he really ignores all the preparatory 

 stages of their existence, and scarcely alludes to the fact of their 

 having possessed life : it is on this ground that I think the lepidopterist 

 more likely than the coleopterist to appreciate justly the teaching of 

 variation. 



Let us then confine our attention to the Lepidoptera on this sole 

 ground, the better knowledge of their preparatory stales, the certainly 

 I may say with which we associate all the individuals of one brood, 

 however they may differ. 



Sexual Variation. 



1. Disparity in Size. — The first difficulty, the primary slumbling- 

 block in our path in every search after truth, is hypolhesis : nothing 

 has delayed the truthful explanation of the phenomena of the solar 

 system so effectually as the vague hypotheses so pertinaciously 

 supported by authority ; it is thus with every inquiry into the secrets of 

 Nature ; and it is because you, my dear sir, dare to look Nature fully 

 in the face, and to inquire what is, rather than what ouylit to be, the 

 method she adopts, that I have connected your name with these 

 investigations. On the very threshold of our inquiry into sexual 

 variation we find the Darwinians, or as we may call them the evolu- 

 tionists, have placed an enormous stumbling-block : they say that the 

 females of insects are larger than the males : in order to establish their 

 views this ought to be so, but it is not. Let the genera Lucanus and 

 Dynastes — they are the most easy of reference — reply. I have urged 

 this repeatedly in conversation, and have compelled those who maintain 

 the hypothesis to take refuge in the Lepidoptera. Allow me to explain 

 my dissent from the now prevalent opinion on this subject, even as 

 regards Lepidoptera. 



The diurnal Lepidoptera exhibit a certain amount of disparity in 

 the magnitude of the sexes, and the females have the advantage, but 

 it is only necessary to arrange a series of any species by the size of 

 the individuals, and it will become very evident to those who can 

 readily distinguish the sexes, that the twenty-five smaller individuals 

 are by no means invariably males, nor the twenty-five larger ones 

 females; but the males and females alternate with something 

 approaching to regularity. The largest and most familiar groups of 

 nocturnal Lepidoptera are the Ursinae, the Geometiae and the Noctua?, 

 but in neither of these does any rule obtain. Beginning with the 



