( Ixxxiv ) 



could wake up in say a thousand years, we should be able to 

 detect changes in the patterns of some butterflies. Although 

 I am afraid the advance of science is not likely to be sufficiently 

 rapid in our time for me to hold out any prospect of such an 

 experience for any of you, there is every reason why we should 

 afford this opportunity to posterity. A critical examination 

 of the fragments of many species of butterflies captured ninety 

 years ago by Burchell in S. Africa, and gnawed to pieces 

 during his Brazilian travels from 1825 to 1830, renders it 

 probable, nay, almost certain, that with moderate care, insect 

 pigments will endure for an indefinite period in our museums. 

 One important justification for the great and permanent 

 outlay required to bring together and maintain large collec- 

 tions of insects is, that we are allowing our successors the 

 chance of detecting and measuring the rate of specific 

 change.* And, as I have already said, for this purpose the 

 Lepidoptera stand pre-eminent. 



For the purpose of the inquiry this evening, our instances 

 will be drawn from the Lepidoptera rather than other Orders 

 of insects, because of the numberless examples of subtle 

 distinction between forms which but yesterday, so to speak, 

 became separate ; because of our knowledge, insufficient but 

 considerable, of their geographical ranges; because of our 

 experience, excessively imperfect and scanty, but still much 

 larger than in other Orders, of inter-breeding and of descent 

 from parent to offspring. 



First among the attempts to define species must be placed 

 that which we rightly associate with the name of Linnseus. 



It has been admirably pointed out by the late Rev. Aubrey 

 L. Moore, f that the dogma of the fixity of species is entitled 

 to none of the respect which is due to age. " It is hardly 

 credible to us," he wrote, "that Lord Bacon, 'the father of 



* Kavl Jordan argues with great force in favour of specialisation in 

 this direction by our museums. (See "Novitates Zoologicte," vol. iii, 

 December 1896, pp. 431-433.) The Burchell collection from Brazil is 

 only seventy-four to seventy-nine years old, but the species are numerous, 

 and often represented by long series. An account of the butterflies by 

 Miss Cora B. Sandeis will shortly appear in the " Annals and Magazine of 

 Natural History" ; and it will then be seen that the evidence of change 

 in certain forms is by no means wanting. 



t "Science and the Faith," London, 1889, pp. 174 et seq. 



