criAP. XVI.] 



THE BRITISH ISLES. 



3i>5 



modified by the particular conditions of the lake in which they 

 have found themselves isolated. 



Peculiar British Insects. — We now come to the class of insects, 

 and here we have much more difficulty in determining what are 

 the actual facts, because new species are still being yearly dis- 

 covered and considerable portions of Europe are but imperfectly 

 explored. It often happens that an insect is discovered in our 

 islands, and for some years Britain is its only recorded locality ; 

 but at length it is found on some part of the continent, and not 

 unfrequently has been all the time known there, but disguised 

 by another name, or by being classed as a variety of some other 

 species. This has occurred so often that our best entomologists 

 have come to take it for granted that all our supposed peculiar 

 British species are really natives of the continent and will one 

 day be found there ; and owing to this feeling little trouble 

 has been taken to bring together the names of such as from 

 time to time remain known from this country only. The view of 

 the probable identity of our entire insect-fauna with that of the 

 continent is held by such well-known authorities as Mr. E. C. Rye 

 and Dr. D. Sharp for the beetles, and by Mr. H. T. Stainton 

 for butterflies and moths ; but as we have already seen that 

 among two orders of vertebrates — birds and fishes — there are 

 undoubtedly peculiar British species, it seems to me that all the 

 probabilities are in favour of there being a much larger number 

 of peculiar species of insects. In every other island where 

 some of the vertebrates are peculiar — as in the Azores, the 

 Canaries, the Andaman Islands, and Ceylon— the insects shoAvan 

 equal if not a higher proportion of speciality, and there seems 

 no reason whatever why the same law should not apply to us. 

 Our climate is undoubtedly very distinct from that of any part 

 of the continent, and in Scotland, Ireland, and Wales we possess 

 extensive tracts of wild mountainous country where a moist 

 uniform climate, an alpine or nortliern vegetation, and a con- 

 siderable amount of isolation, offer all the conditions requisite 

 for the preservation of some species which may have become 

 extinct elsewhere, and for the slight modification of others 

 since our last separation from the continent. I think, therefore, 

 that it will be very interesting to take stock, as it were, of our 



