NOTES ON THE DISTRIBUTION OF THE BRITISH COLEOPTERA. 203 



England, but a few appear as isolated detachments in suitable localities 

 as far east as Surrey and south as Devonshire. (2) We have 

 a large assemblage comprising, in fact, the bulk of our species, which 

 forms an area of greatest density in the south-east, gradually thins out 

 west and northward, till the species become generally rare, and are in 

 many cases entirely absent from Scotland and Ireland. (3) The third 

 group is, perhaps, more diflficult to define, and its members cannot 

 always be disentangled from those of the second division. I should 

 comprise in it all those species whose distribution is c.nindvehj 

 southern and south-eastern, and it is often marked even in the limited 

 area of its range by extreme discontinuity and specific rarity. (4) We 

 have a small assemblage of species which either occur only in Ireland, 

 but are not there restricted to the nortb, or which occur in England, 

 only, or in greatest abundance, in the extreme south-west, and with 

 this group I should feel inclined to associate a few species which 

 inhabit only or principally the shores of the Bristol Channel. 



NoAV, as already stated, we are by no means able from the very 

 slight, incomplete, and sometimes even erroneous data which we 

 possess, to go through the list of our British coleoptera and assign, 

 even with the exceptions previously noted, every species to one or other 

 of these groups. They are at least more or less approximate generali- 

 sations, and to enumerate the species which we can so assign would 

 be superfluous to the coleopterist reader, and tedious to any other. We 

 may, however, consider these four groups a little more in detail. 



Our first has been called the Arctic, Glacial or Celtic element in 

 our fauna, all terms which to some extent beg the question, perhaps 

 the Celtic is the better name, if we can eliminate any connotation with 

 the Celtic race ethnographically considered. Now the distinctive 

 points about this group are, that its area of maximum density is in the 

 north-west, tbat none of its members occur in England or Wales 

 which do not occur in Scotland or Ireland, or both, but that several 

 species are found in the latter, which certainly have not yet been 

 discovered in England or Wales, although environments in every 

 respect suitable may exist there. The group outside these islands 

 extends over the whole of northern Europe and the coleopterous fauna 

 of Faroe, Iceland, and Greenland, as far as it is known, is represented 

 in it. The question then arises whence was this element, distinct, 

 homogeneous, and separate as it is in our fauna, derived ? 



If we assume the destruction of all life during the glacial period, or 

 a total submergence of these islands since or during that period, this 

 derivation could only have been from the south or east, for if ex 

 In/jiiit/u'si Glacial conditions made life impossible in these latitudes still 

 more would the derivation of any life from still more northerly areas 

 have been impossible, and we have excellent geological reasons against 

 assuming any great western continental extension of land since the 

 close of the tertiary period at least. Thei'efore this assumption requires 

 that all those species which we now find in the north and west must 

 have travelled there from the south and east. Yet of this journey we 

 can find no trace". Why was not Di/tiscKs lajipaiticKs left in the 



* The occuirence of Carahu.^ clathralus in Norfolk, if it rested on absoliitoly 

 iiMiuipeacliiil)le evidence, would undoubtedly be a Inicc of the kind incaMt, but 

 hardly tiufficient to prove that this speciea reached Donegal and the Hcbridc^^ rio 

 East Ani'lia. 



