22 ORIGIN OF LIFE IN AMERICA 



have survived the Glacial Epoch in Greenland, yet several 

 authors who have written on the lepidopterous fauna of that 

 'country maintain that the theory of a former land bridge 

 with Europe and North America is quite consistent with the 

 facts of distribution. Mr. Petersen,* for example, concludes 

 from his studies that land connections in high northern lati- 

 tudes enabled certain arctic butterflies and moths to spread 

 from a polar centre to Europe and North America. After 

 alluding to a large number of moths common to Canada and 

 Europe, Mr. Girard f emphasises the significance of this fact 

 as indicating the former existence of a land bridge between 

 North America, Greenland and, Europe. 



Although no butterflies occur in Iceland, Coleas nastes, 

 Argynnis chariclea and A. polaris are known even from the 

 barest and most exposed districts of Greenland, where 

 nothing but Dryas octopetala and some slender grasses grow. 

 These species have a wide range in boreal America, Europe 

 and Asia, but of the nine butterflies known from the arctic 

 American archipelago five are European, while only two are 

 met with in Asia, according to Dr. Pagenstecher. Many 

 striking examples, showing the relationship between Green- 

 land and the neighbouring continents occur among the moths, 

 especially among the Noctuidae. Anarta melanopa inhabits 

 only Colorado, the White Mountains, Labrador, Scandinavia, 

 Scotland and the Alps. Anarta leucocycla and A. lapponica 

 are found in Labrador, Greenland and Scandinavia. Mr. 

 Grote J alludes to no less than twenty-eight other Noctuids 

 that are common to Europe and North America, even ex- 

 cluding those met with in Labrador or circumpolar species. 

 All these facts tell in favour of the view I have endeavoured 

 to elucidate. 



No matter what group of terrestrial invertebrates we 

 choose, similar close relationships may be discovered between 

 American and European species, which cannot be explained 

 by the assumption of a former land connection across Bering 



* Petersen, W., " Lepidopteren-fauna d. arkt. Gebietes, p. 44. 

 t Girard, Maurice, " L'Entomologie de PAmerique du Nord," 

 p. 287. 



| Grote, A., "Noctuidae of North America," p. 313. 



