A T zt Correspo7idence. L J "'>' 



dication of the complete maturation of the whole organism, so fur as 

 regards the first assumption of the nuptial plumage by young birds. In 

 respect to the older birds, the donning of the nuptial dress and activity of 

 the sexual organs are coincident phenomena of the breeding season, but 

 that the latter is not necessarily the cause of the former seems evident 

 from the breeding of young male birds before acquiring the nuptial dress, 

 as is well known to occur in many species, familiar examples of which 

 being the Purple Finch, the Redstart, and the Orchard Oriole. The 

 subject, however, is an important one, well worthy of the most careful 

 investigation. — J. A. Allen, American Museum of Natural History^ Tjht 

 St. and Sth Ave., Neiv York City. 



CORRESPONDENCE. 



\_Corresponde7its are requested to write brietiy and to tlie point. No attention will 

 be paid to anonytnous communications.^ 



The Classification of the Macrochires. 



To THE Editors of the Auk : — 



Sirs: Recent examinations of nine of the skeletons of the representa- 

 tives of the three sub-orders of birds (Caprimulgi. Cypseli, and Trochili) 

 now constituting, according to the Check-List of the American Ornitholo- 

 gists' Union, the order Macrochires, convince me, so far as skeletal char- 

 acters go, that we are retaining in the same order birds that undoubtedly 

 belong to very different orders. There is no question in the world but 

 that the Swifts are widely separated from the Hummingbirds, and a com- 

 parison of the structural characters of any of the forms of these two 

 groups will at once convince us that they are fully entitled to ordinal rank. 

 The Cypseli are profoundly modified Passeres, coming nearer the Swal- 

 lows in their organization than any other group of birds, and should be 

 awarded a place in the system accordingly. On the other hand, the 

 Trochili are fully entitled to an order by themselves, and further investi- 

 gations are necessarv to ascertain how they are approached, structurally, 

 by other groups. 



Again, this classification will leave the Caprimulgi standing out by 

 themselves, as they undoubtedly- should do. in an order of their own, as an 

 examination of their organization goes to show that they have but little in 

 common with the Cvpseli. and are widely separatee! from the Humming- 

 birds. 



My preliminarv examination into the structure of this group has just 

 been published (Dec. i, 1885) in the 'Proceedings' of the Zoological So- 

 ciety of London, where much will be found which the limitations of space 

 will prevent me from discussing here, but further investigations in the 

 directions pointed out are of the highest interest and importance. It is 



