PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 457 



liabits, while the more rounded wings are oftener found in stationary 

 birds. This fact, however, does not in any way diminish the value of 

 the structural diiference as a distinguishing mark, the purpose of which 

 is to indicate the limits of the different generaj nor is it without impor- 

 tance in indicating the affinities of the ditferent forms. In so far as it 

 is connected with the migratory habits of certain species, it j)robably 

 signifies the simultaneous immigration of those birds into the region to 

 which they now belong, and indicates thus a geographical separation 

 which, during the course of time, cannot have been without influence on 

 their development. 



That the more or less rounded or pointed form of the wing has not 

 such an essential importance in regard to the migratorial phenomenon 

 is evident from the general consideration, that not all migratory birds 

 have long and pointed wings. It is also to be remarked, that in general 

 the same species is migratory in some localities, while in other places 

 it is stationary. Finally, we have in the group of birds here under con- 

 sideration ample opportunity for showing instances which i)oint to quite 

 the opposite direction. So. for example, has Ridgicayia pinicola — which 

 certainly is not a migratory bird, and the geograj)hical range of which 

 is remarkably restricted very pointed wings, with the 3d and 4th 

 quills longest, and very short secondaries. We have also the genus 

 Sialia, with its unusually lengthened and pointed wings. 



On the other hand, the length of the secondaries and of the primary 

 coverts seems to be of very great importance. Kor is their length in 

 any way directly dependent upon the migratory or stationary habits of 

 the birds, though it may certainly be admitted that longer secondaries 



outer taperiug from about its luiddle. Bill somewhat lengtheued, rather weak, broad 

 at base; nostrils large, rounded, much exjjosed; frontal feathers not reaching by far 

 to the posterior margin. Tarsus scutellate anteriorly, as long as middle toe and claw. 



Myiadestes Icvcotis, Cab. 



Professor Baird states that the tarsus is " without distinct scutellar divisions* ante, 

 riorly except below," but a close examination shows that there is a well, marked divis- 

 ion straight above the upper division of the outer side. The accompanying figure. 

 No. 41,908, is also less correct in another respect, showing the nostrils too near the 

 feathers of the forehead. 



