buttcniics of the French Pyrenees. 408 



On the whole it is rather surprising that a range of 

 mountains so extensive, so high, and so isolated as the 

 Pyrenees should have developed so few distinct forms 

 among the Lepidoptera. and should have so large a 

 proportion of those inhabiting the Alps, which seem so 

 completely separated from the Pyrenees by the great 

 plains and low dry hills of Southern France. This is 

 not the ease among plants, of which there are. 1 think, 

 a very much larger proportion of peculiar species in the 

 Pyrenees: whilst a much greater number of common 

 Swiss alpine plants are absent. I shall he glad to hear 

 from entomologists whether this absence of peculiar 

 spirits in the Pyrenees is also the case in other orders 

 of insects, and how it is to he accounted for. 



