THE ARCTIC FAUNA. 167 



to Western Europe and North America, though an 

 allied species, Gasterostcus sinensis, lives in China and 

 has probably penetrated there from the New World 

 across the old Behring Straits land-connection. 



The Coleoptera Diachila arctica, Elaphrus lapponicus, 

 and Blethisa multipunctata are good instances of 

 species which have come to us from North America 

 by way of Greenland. I have already referred to 

 the Lepidoptera, but might add that eleven species 

 of Anarta occur in Scandinavia, eight of which 

 reappear again in Labrador, none of them, however, 

 being met with in Siberia. Then again, take the in- 

 teresting Crustacean Lepidurus (Apus] glacialis. It 

 is found in Greenland, Spitsbergen, Lapland, and 

 Norway; and formerly, as we know from fossil 

 evidence, it ranged into Scotland. Another Phyllo- 

 pod, viz., Branchinecta palndosa, inhabits Greenland, 

 Lapland, and Norway. Mr. Kennard suggests that 

 the freshwater Snail Planorbis glaber might also 

 belong to the same migration. And there are no 

 doubt large numbers of others. 



Professor Emery mentions that Northern Europe 

 possesses one peculiar genus of Ant, viz., Anergates. 

 This is closely allied to Epoccus, another genus con- 

 fined to North America. It seems probable, there- 

 fore, that both of these have sprung from an Arctic 

 genus which sent two branches southward into the 

 two continents without there being any migration 

 through Asia. 



The general range of the Arctic plants and animals 



