59 



being not only deeper and more extended, but the brown of the body is 

 darker and richer ! Kegarding the bl ack bil 1 of the southern form , supposed 

 by Mr. Allen to characterize it alone, we now know that in all the forms 

 it is black in summer, while, even in australis itself, it is yellow in winter ! 

 The fact that littoralis has more gray on the head than tephrocotis cannot 

 be explained by stating that the former is more northern in its distribu- 

 tion, for such is not the case, since the breeding-ground of var. tephrocotis 

 is quite as far northward in the interior as that of var. littoralis is on the 

 coast. We must, therefore, look to some other explanation of these vari- 

 ations than the laws of climatic modification which are now recognized. 



The single instance of apparent correspondence to a general rule of 

 geographical variation is seen in L. griseinuclia of the Alaskan coast^ 

 which is more northern in its habitat than L. littoralis of the more 

 southern North-Pacific coast, and is also larger in size. 



Mr. Aiken's notes upon the relation of the several forms are worthy of 

 publication, and are consequently presented verbatim* 



" I sent to you, some ten days since, a box containing, besides some 

 hawks, etc., over two hundred specimens of Leiicosticte ; these forming, 

 with one or two exceptions, my entire series of the genus. So large 

 a series, embracing as it does specimens from various localities and 

 of different dates of collection, should, I think, throw considerable light 

 upon the genus. Of australis, you will find specimens collected from 

 February to May 15 ; and, ot tephrocotis, from January to April. . . . 

 . . . It seemstometha,t the chain connecting tephrocotis and griseiniichaf 

 is very complete, the gradation being almost imperceptible, and I see 

 no good reason for admitting so many varieties unless these varieties 

 are restricted during the breeding-season to distinct localities."! 



" Were it not that I dislike to believe in hybrids, 1 should think that 

 griseinucha and tephrocotis were distinct species, and that the intermedi- 

 ate forms were the results of interbreeding. If atrata were a southern 

 race of tephrocotis, would j'ou not expect it to be smaller ? On the other 

 hand, it is, if any different, larger." 



SEASONAL VARIATIONS. 



The variations with season are so well defined and regular that they 

 may be easily understood. In all the forms, the bill is yellow, black-tipped 

 in winter, and uniform black in summer. In the latter season, the soft 

 rosy pink of other seasons is changed to a more crimson or carmine 

 hue, and the paler borders to the contour- feathers disappear. These 

 facts borne in mind, another important one is to be impressed on the 

 memory, i. e., that there is not the slightest alteration of the pattern ! In 

 all the forms of tephrocotis, the gray of the head remains precisely the 

 same throughout the year. L. australis never has any gray on the head, 

 while it is probable that in L. atrata the same constancy of this feature 

 obtains as in L. tephrocotis. The changes from the winter-dress to that 

 of summer are thus explained by Mr. Aiken, before quoted : "Up to 

 the 20th of March, all birds killed had the bill yellow ; but in the last 

 grand haul, on April IS, of more than three hundred and fifty specimens, 

 all had a black or nearly black bill, so that the change in the color of 



* Letter to the author, dated June 20, 1874, referring to the specimens tjansmitted fo." 

 examination. 



t At the time Mr. Aiken supposed his specimens of HttoraUs to he griseinucha ; the latter 

 he had not seen. 



t Such proves to be the case. 



