The human transport of animals across the Northern Atlantic 



153 



(Photo P. Ardo.) 



FIG. 14. Distribution of long-winged (white) and short-winged (black) specimens 

 of the Carabid beetle Notiophilus biguttatus F. in Newfoundland, its single occurrence 

 in North America. The area of the circles is in proportion to the number of individuals 

 investigated. 



Short wing is a dominant; consequently, long-winged specimens are homozygotes 

 and a preponderance of them indicates late colonisation. This species is a European 

 introduction, spreading from the Avalon Peninsula in the southeast towards the west 

 and north. 



Ottawa, 1891; Clivina fossor at Montreal, 1915. These have since been obviously 

 enlarging their area and so, with unusual rapidity, has Pterostichus melanariuSy 

 first found in Nova Scotia in 1926. 



2. On GEOGRAPHICAL evidence. Nebria brevicollis, Bembidion lampros, and 

 Pterostichus strenuus are known in eastern North America each from one quite 

 small area only, the Nebria on the French island Miquelon, the remaining two on 

 the eastern shore of the Avalon Peninsula. A pronouncedly "unnatural", disjunct 

 area in Newfoundland is occupied by Agonum ruficorne, Bembidion tetracolum 

 (fig. 12), Carabus nemoralis, Clivina fossor (fig. 13), and Trechus rubens. A large- 

 scale disjunction, suggesting introduction into North America on the whole, is 

 characteristic of Agonum miilleri, Amara familiaris, Bembidion lampros and tetra- 

 colum, Carabus nemoralis (fig. 7), Clivina fossor, Harpalus af finis, and Pterostichus 



