52 Mr. Elliott Coues on Picicorvus columbianus. 



breast yellowish brown, a few white spots on the scapulars, 

 and indications on the outer webs of some of the primaries ; 

 tail dark brown, and white spots on middle feather ; bill greenish 

 at tip, blackish at base. 



From the specimens before me, it would appear that this 

 species is very dark when young, and without spots, but becomes 

 lighter and more spotted as it becomes older, and puts on the 

 dress of the mature bird. At all stages of plumage, however, 

 it shows the white over the eyes and at the base of the bill, 

 which caused its first describers to give to it the name of 

 albifrons. 



VITI. — Observations on Picicorvus columbianus. 

 By Elliott Coues, M.D., U. S. A. 



I HAVE no hesitation in inviting your attention to a bird that 

 lacks a biographer, though it is one thoroughly known in the dried 

 state. By bringing together the substance of several detached 

 notices that have appeared, and adding, it may be, some further 

 information obtained whilst I was in the West, we may have an 

 account deficient in little, if any thing; 



I should not even allude to the well-known intimate affinity 

 of darkens Crow with the European Nutcracker, did I not pur- 

 pose to illustrate by this means a rule of some general apphca- 

 bility. In this case of typical representation of one genus by 

 another, we have an excellent example of the fact that a num- 

 ber of European birds find their nearest American relations in 

 the species of Western North America, instead of those of the 

 eastern province. Sometimes there is actual specific identity ; 

 again there is only a differentiation of the same species into 

 geographical races, frequently with positive specific distinctness ; 

 in birds of the same genus, either the genus itself is confined to 

 the West, or else, while the genus reaches across America, its 

 western species are more particularly like the European than its 

 eastern ones are; and, lastly, certain genera, confined to the 

 West, are strictly locum tenentia of European genera. In the 

 following Table examples of each of these kinds and degrees of 



