Author's preface 



1 he incentive to this book was given by entomological fieldwork in Iceland 

 (1926 and 1929) and Newfoundland (1949 and 1951). 



The former island has a veritable key position in the northern Atlantic, situated 

 almost three times as far from the European mainland (Norway) as from Greenland 

 but in spite of this inhabited by an almost purely European fauna. This fact leads 

 to the assumption that a considerable part of the Icelandic fauna immigrated from 

 Europe in an interglacial period when land had a greater extension in the North 

 Atlantic. Parts of this faunal element apparently even succeeded in colonizing 

 Greenland. 



An attempt was made to investigate the insect fauna of Newfoundland from the 

 same point of view, i.e. to discover a "European" element in the fauna of this 

 island too. The results obtained were unexpected, in more ways than one, and it 

 soon became clear that a satisfactory understanding of the faunal history of the 

 islands in the North Atlantic called for a general faunistic survey of the continents 

 of Europe and North America, at least for selected, sufficiently investigated and 

 otherwise suitable groups of animals. 



From this enlarged amount of data, the attempt to explain the trends of animal 

 distribution in the islands considered was transformed into a comparison between 

 the Palaearctic and the Nearctic terrestrial fauna as a whole. It was also necessary to 

 consider the results obtained by botanists who, in biogeography, are often ahead 

 of zoologists, to benefit by palaeozoological evidence (when available), and— 

 finally— in order to understand the importance of dispersal of animals by human 

 agencies, to get an idea of the North Atlantic trade during the last four centuries. 



This was a diversified and fascinating study, but dangerous at the same time. 

 It is perhaps to be regretted that a specialist in Carabid beetles, like the cobbler, 

 is not always wise enough to stick to his last. 



