• ° j,jj*4 " J DwiGHT, Plumages of the Scoters. 295 



six species in the genus Oidemia, the heads of which (Plate XXIV) 

 have been drawn and colored true to life and in most cases from 

 fresh birds by Mr. Henry Thurston. The feathering of the bills is 

 diagnostic of each in all plumages. 



The question of genera need not detain us long. I am not one 

 who believes in making generic distinctions so fine that nothing 

 is left except monotypic groups and it seems to me that there 

 should be some difference between a genus and a species. Unless 

 we recognize the six species now in Oidemia as congeneric, there 

 should be six genera. Fleming (Philos. of Zool., ii, p. 260, 1822) 

 established the genus Oidemia (later spelled CEdemia) and although 

 five other genera have since then had more or less vogue, there 

 seems no good reason for recognizing any of them. 



In view of all that has been written about the Scoters during the 

 many years that they have been known to ornithologists, it would 

 seem superfluous to add to a literature that already seems replete 

 were it not that very little has been published bearing directly 

 upon the moult itself and the way that it is related to plumages. 

 Over a dozen years ago I took up the study of the moult of the 

 Scoters making use of specimens that were freshly killed. In this 

 way it has been possible for me to follow the plumage changes 

 much more accurately than merely with dried skins and now with 

 the large series at hand that were first so studied, I am prepared to 

 show some new facts and correlate a good many others that have 

 been imperfectly understood. My own collection includes the 

 following specimens, viz. Oidemia am,ericana, 18 adult males, 6 

 adult females, 10 young males and 3 young females; 0. perspicil- 

 lata, 23 adult males, 6 adult females, 21 yoimg males and 10 young 

 females; 0. deglandi, 23 adult males, 9 adult females, 10 young males 

 and 22 adult females; 0. carbo, 2 adult males; 0. fusca, 3 adult 

 males; and 0. nigra, 3 adult males, 1 young female, and 1 downy 

 young. The bulk of my specimens came from Long Island, New 

 York, but besides my own birds I have examined fully as many 

 others in other private and public collections kindly placed at my 

 disposal. As a consequence I have had no dearth of material 

 except perhaps of breeding birds, and have been able to piece out 

 very complete series of most of the species, representing every 

 month in the year. 



