266 



CHAPTER III 



(Photo P. Ardo.) 



FIG. 40. The distribution oi Amara alpina brunnipennis Dej. in eastern North America 

 and the Canadian Arctic. This Carabid beetle occurs also in Alaska and in the moun- 

 tains south to Colorado. It is probably constantly flightless. The figured specimen 

 is from Labrador. 



pilaris L.) reached Greenland, probably from southwestern Norway, in 1937, and 

 gave rise to a permanent colonization (fig. 42). Similarly, the Palaearctic Gamma 

 Moth, Plusia {Phytometra) gamma L., captured in both eastern and western 

 Greenland, is surely a casual immigrant since it is normally not able to survive 

 winter even in Scandinavia. 



From zoo- and phytogeographical facts it is easy to demonstrate, however, that 

 eastzvard dispersal, passive or semi-active, occurs more regularly in the North 

 Atlantic area. The American element in the British flora has little equivalence in 

 North America (p. 251), this applies also to the Noctuid Moths and a few other 

 flying insects of American origin which invaded Iceland and the Faeroes (p. 253). 

 Though several Nearctic species of winged insects and "ballooning" spiders have 



