2 



MR. A. MURRAY ON THE GEOGRAPHICAL RELATIONS OE 



tions which may, and occasionally does, enable seeds to be carried 

 in the stomachs of birds or floated across wide oceans to distant 

 lands *. They have also the advantage over the larger and more 

 highly organized animals in that they can survive and find food 

 where the latter could not. Their food is so various that nothing 

 but a total extinction of all other life could wipe them off from 

 the face of a country — a partial submergence of land for even a 

 short period might destroy every mammal upon it, but so long as 

 a tree-top is above the flood or an uncovered rock remains on 

 which they can take refuge, the life of the Beetle class is safe 

 when the waters abate. A succession of cold seasons in which no 

 plant can bloom might destroy those kinds of animals for which, 

 like the bee, flowers and honey are necessaries of life, some bee- 

 tles might indeed then go ; but there are plenty that feed on leaves 

 or stems to preserve the Beetle type in the frozen land. Their 

 numbers, too, multiply the chances of escape in the case of dis- 

 aster, and their powers of flight enable them to take advantage of 

 such as occur. Further, the powers of flight, although sufficient 

 for a moderate distance, are not like those of birds, so great as to 

 carry them to new lands at great distances and so to risk the dis- 

 turbance of faunas which such powers, if possessed by such mul- 

 titudes, might possibly produce. In many respects, too, they are 

 as much adstrieti glebes as plants themselves, for a vast host are 

 limited each to one particular plant for food. As in plants, in- 

 deed, there are some kinds of Beetles more open than others to 

 the suspicion of having been introduced from one isolated land to 

 another, as, for example, the timber-borers or Longicorns. But 

 there are others, as the hunting or carnivorous species, the apte- 

 rous species, the blind insects, and others of less specialized struc- 

 ture, whose presence in discontiguous countries seems to bid defi- 

 ance to any explanation other than that of former continuity of 

 soil. In Madeira, for instance, where the number of admittedly 

 introduced species is very great, there is not one introduction be- 

 longing to the hunting families ; and if this is the case there, not- 



* It is a digression, but it is worth making one, to point out that if plants can 

 be disseminated in the way supposed, and Beetles, or certain families of Beetles, 

 can not, the attempt to explain the distribution of the former as due either 

 solely or mainly to these means must be abandoned in every case where their 

 distribution corresponds with that of the latter. The common elfeet must have 

 been produced by a common cause. And it so happens that this correspondence 

 exists in all the more important and puzzling facts of distribution. 



