DERIVATION OE BRITISH COLEOPTERA. 175 



They may also afford evidence of a former land connection 

 which, closing in the Atlantic on the North, united 

 Ireland, Scotland, Norway, Iceland, and Greenland. Such 

 a continental land extension might well have been the 

 home of what we call the Celtic element in our western 

 fauna, as well as the bridge which carried those American 

 species which we recognize both in the Irish flora as well 

 as fauna. Thence any immigration would have been from 

 the north-west, south and eastwards, which is what the 

 facts of our Coleopterous distribution of this group require. 

 The difficulty comes in when we attempt to harmonize 

 this theory with preconceived notions of the severity of 

 glacial times, for, of course, if that severity were such as 

 to forbid the existence of animal life in Great Britain, 

 still more would it be impossible in this hypothetical 

 northern land, and any migration would necessarily have 

 had to proceed from the south northwards. If, however, 

 we may be allowed to suppose that the British glacial 

 climate after all might have permitted the continued 

 existence of this Celtic fauna, then we see no difficulty 

 in conceiving that fauna, as originally a pre-glacial one 

 inhabiting a region to the north-west, now lost and driven 

 southward by the advent of glacial conditions which cer- 

 tainly would have made such a northern land untenable, 

 instead of led up northwards frotn the south on the 

 cessation of such conditions. In any case, I think we 

 may look upon the species comprised in this first group 

 as distinctly older residents than the vast mass of species 

 whose advent was more indubitably from the south and 

 east, and perhaps this is as much as one can safely say. 



Proceeding, then, to a consideration of our second 

 group, we see no reason to doubt that their advent was 

 from the east and south-east at a time when the German 

 Ocean was dry land. The distribution of some of them is 



