Coleoytera of the Canary Islands. 139 



theory, which we have been told it is most " unphilosophical " to 

 doubt. Here are seven large islands, the lower and intermediate 

 regions of which were originally more or less densely clothed with 

 various gigantic Euphorbias, nourishing an entire fauna of their 

 own. By degrees the Euphorbias are becoming destroyed (col- 

 lected by the inhabitants for fuel), and in immense tracts they have 

 already totally disappeared. Now, what is the consequence? Are 

 the creatures which infest them to adapt themselves gradually to 

 altered circumstances and a different kind of food, becoming (to 

 however slight an extent) modified accordingly 1 or shall they, on 

 the other hand, die-out? Our theorists must, in consistency with 

 their own principles, say the former ; but if we go to nature for a 

 reply, she pronounces, unequivocally, the latter ! Nor can this be 

 regarded as a mere isolated fact, to be at all accounted for by cir- 

 cumstances of an exceptional kind, and one therefore from which 

 we cannot properly generalize ; for it applies to upwards of thirty 

 well-defined species, swarming by myriads over extensive tracts 

 of country widely separated from each other and variously con- 

 stituted ; — so that there is nothing "exceptional" about it; it is 

 merely the common result of a gradual change of external in- 

 fluences brought to bear on a whole fauna which was specially 

 created for a peculiar race of plants, and such as might have been 

 anticipated beforehand by the most ordinary practical observer. 

 It is precisely analogous to the case of the laurel-fauna, which 

 (through a similar cause) is in like manner fast disappearing from 

 the Atlantic groups, and which in some of the islands has abso- 

 lutely gone, — leaving no vestige behind it of any one species which 

 can possibly be supposed (from the knowledge, gathered else- 

 where, which we actually possess of them) to have been in any 

 way connected with, or derived from, the original forms. 



1 will just add, that eight only of the Coleoptera enumerated 

 below have been detected also at Madeira, namely, Europs impres- 

 sicolUs*, Lcemophloeus clavicollis, Corticaria maculosa, Aphanartlirum 

 bicolor* and piscatorium*' , Leiparthrum curtum and inarmatum* 

 and Homalota coriaria, — merely half of them, moreover (to which 

 an asterisk is affixed), being of exclusively Eupho^'hin-infesUng 

 habits. But since the Euphorbias are very much less numerous 

 in that group (both specifically and individually) than they are at 

 the Canaries, this is simply in accordance with what we might 

 anticipate. Still, it must be noted that there are a few species-j- 



t Such are llie Aphanarthrum and Mesttes F.uphorhi.r, CanlotrKpis fuhniiidim, 

 Hypoijlilouus amhi.giius and Oinaliam clavicoriie. 



