146 Stejneger on the Ge?tus Acanthis. [April 



= iSi6. — -Linaria Vieillot, Anal. p. 30 (nee Bechst. 1803, nee 



BOTAN.)- 



= 1S51. — Acgiothus Cabanis, Mus. Hein. I, p. 161. 



^ 1S60. — Acanthys DeMurs, Tr. d'Ool. pp. 334, 546. 



In the first place I have to state, that an inspection of my 

 ample material plainly shows that Mr. Ridgway was completely 

 right, when he separated the white Greenland Redpoll {^^canes- 

 celts' = hornemaniiii) specifically from A. linaria, and that he 

 was also right in placing exlllpes as conspecific with the former 

 and not with the latter. It is hardly necessary to remark, that 

 no intergradation can be detected between the two typical forms, 

 and not even — and I should say much less — het\yeen. kornefnait- 

 nli and the Greenland form of linaria. Jt is between the latter 

 and the race exilipes of the former, that intergradation has been 

 supposed to occur. But this intergradation is either only 

 apparent, because it sometimes is difficult to distinguish yoiing 

 birds of the two species, or it originates in hybridization. Of 

 all the adult males which I have had the opportunity to examine, 

 only one presented characters somewhat intermediate, thus creat- 

 ing the suspicion of its being a hybrid ; but it was essentially a 

 small linaria, to which species I referred it without much hesi- 

 tation. That the two species really interbreed has, however, 

 been observed in Alaska by Mr. E. W. Nelson, if we are cor- 

 rectly informed. 



I need not point out the differences between these two species, 

 as they are completely fiuriiliar to all North American ornitholo- 

 gists, but I want to call attention to the fact, that exilipes grad- 

 ually becomes smaller going from the East to Alaska and 

 Northeastern Asia. The decrease in size is. however, so gradual, 

 and the difference so small, that the eastern and western birds 

 cannot be separated, especially since there cannot be detected the 

 slightest difference as to color. Von Homeyer indicates that the 

 Asiatic specimens probably have the red more intense than those 

 from America, but I can match a rather vividly colored specimen 

 collected by me on Bering Island with specimens from the interior 

 and the eastern part of North America. 



Nor will it be necessary to treat at length of the difference 

 between exilipes and its Greenland representative, hornemannii 

 (r= canesceits Bp. nee Gould). The extremes are easily distin- 

 guished by the thicker and stouter bill of the latter, and its decid- 



