No. VI. mSECTA. 239 



and no butterfly is known from either. Thus we see that 

 Grinnell Land, ice-bound and ice-covered as it is for all but 

 a short period in each year, possesses an insect fauna that 

 cannot be styled otherwise than remarkable, and which in 

 butterflies is probably richer than Greenland. 



The aspect of the fauna is decidedly what has been termed 

 ' Scandinavian,' but I regard the representatives as the 

 remnants of a once more extensive Arctic fauna, which came 

 in, or was developed, after the close of the warm Miocene 

 period, and culminated before the glacial epoch ; and in this 

 am disposed to agree with the late Edward Forbes in a theory 

 advanced in 1846, in an attempt to account for the geological 

 relations of the fauna and flora of the British Isles, and 

 which has been accepted by many leading naturalists and 

 geologists. According to this theory, the common origin of 

 the existing Alpine and Arctic flora and fauna is explained. 

 When the glacial period ceased, plants and animals began to 

 move northward ; some found a congenial home on the top of 

 high mountains, and established the existing Alpine flora and 

 fauna, whereas others reached the home of their ancestors in 

 the Arctic regions. During the long period that has elapsed 

 since those times, scarcely any modification in Arctic and 

 Alpine forms has taken place in some cases ; in others, in 

 which the divergence is greater, evolution will account for it. 



