ON MELANISM IN LEPIDOPTERA. 95 



same formation produces white butterflies and black moths: 

 for instance, Pieris brassicce and Mania maiira occur in the 

 same locality. However, geological formation may have 

 more to do with the existence of permanent varieties or 

 evolution than we at present think. 



I have before me some closely-allied species, with their 

 anal appendages denuded, in order to compare the difference 

 of structure in different species, and in varieties of ihe same 

 species. There is very little, if any, diff"erence between the 

 anal appendages of Acronycta psi and A. iridens, yet the 

 larvae are very distinct. The sexual organs of Cerasiis taccinii 

 diff'er little from those of C. spadicea, but how far their 

 larvee differ I do not know from experience. I find a slight 

 difl'erence between Epunda lutulejita and its variety Luni- 

 hurgeiisis, hut a. very marked difference between these varieties 

 and E. nigra; also a great diff'erence between Tephrosia 

 hiundularia and T. crepuscularia, as well as between the 

 varieties of Triphcena orbona and T. fimbria. On comparing 

 the anal appendages of a male Crymodes e.xiilis from 

 Iceland with another from Inverness-shire, I found them 

 identical ; until then I believed them to be distinct species. 

 When we discover the larvae of this species in Scotland we 

 shall then be able to determine whether ours is a mere 

 variety of C. exulis or not; but at present I still think it 

 doubtful, because I find the anal appendages of closely-allied 

 species in some cases identical ; and I am certain that the 

 Hadena assimilis of Doubleday has different habits in 

 Scotland from those of C. exulis in Iceland. 



If the doctrine of evolution is a true theory, then these 

 varieties are most interesting : they appear to me to be 

 carrying into eff'ect the laws of Creation before our eyes. It 

 is just as easy for the Creator lo say, "Let there be a man, 

 and there was a man," as to say, "Let there be light, and 

 there was light;" but if the latter was the way in which man 

 sprang into existence, how comes there to be such a race as 

 ours, and another so different as the negro race? Darwin 

 justly remarks, when speaking of races of men: — "Some of 

 these, such as the negro and Einopean, are so distinct, that 

 if specimens had been brought lo a naturalist without any 

 further information, they would undoubtedly have been con- 

 sidered by him as good and true species." So with varieties 



