304 



CHAPTER III 



FIG. 58. Bembidion transparens Gebl. Distribution of long-winged (white) and short- 

 winged (black) specimens in North America. The size of the circles is in proportion 

 to the number of individuals examined. The circle for Newfoundland is strongly 

 underdimensioned {vide fig. 59). 



in Europe at least, was the last but one glaciation (Riss), had the greatest effect 

 (Lindroth, 1935, p. 627). 



The boreoalpine type of distribution is most frequent in Europe because a wide, 

 continuous plain separates the southern mountains from the arctic-subarctic 

 regions of the north. But it occurs also in Asia, as shown by the Three-toed Wood- 

 pecker (fig. 50) and the Carabid Diachila polita Fald. (Lindroth, 1954 c, p. 9), 

 though information as to its extent is not obtainable because of insufficient know- 



