NUMENIUS. 



321 



shore of the Pacific. Returning north, after the ice had disappeared, they spread eastward 

 to the Atlantic, whilst a party crossed the Behring Sea into East Siberia, where they 

 became differentiated into a closely allied, but now perfectly distinct, species. 



Of the two species belonging to this group one breeds in East Siberia and the other in 

 sub-Arctic America. As the latter is more common on the Pacific coast of that continent 

 than on the Atlantic, there is every reason to suppose that this group represents the 

 Curlews which emigrated through Behring Straits along the American shores of the 

 Pacific. 



KEY TO THE SPECIES. 



Tarsus more than three 

 inches long. 



longirostris ■ 



cyanopus. 



Axillaries pale chestnut without 

 bars. 



I 



arquatus 

 lineatus 



Lower back and rump un- j tenuirostris 

 streaked white. 



> phaeopus ■ 



Lower back much paler than 



I mantle 



Crown plain brown with a 

 pale mesial streak. 



Tarsus scutellated both ") 

 back and front. ) 



variegatus 



tahitieusis 

 hudsonicus 

 borealis • 

 minutus • 



f Shafts of feathers on thighs 

 L prolonged to long hairs. 



v Axillaries pale chestnut barred 

 with brown. 



} Scarcely any trace of bars on 

 primaries or secondaries. 



This key to the species and subspecies is a very satisfactory one, showing their mutual 



affinities in a very concise manner. All the characters are found in the young in first 



plumage as well as in the adults of both sexes, except one. The character of lower back 



and rump unstreaked white only applies to adult thoroughbred examples of N. lineatus and 



N. phceopus. The young in first plumage of both species, as well as intermediate forms 



between the former and N. arquatus and between the latter and N. variegatus, have these 



parts more or less streaked. 



2 T 



