ART. 7 CAUDAL MOLT OF BIRDS FRIEDMAlSTlJT O 



irregular in its progression toward the outermost pair; while in 

 Lofhoceros melanoleucus geloensis the molt begins simultaneously 

 with the middle and the outermost pair. 



Wetmore (5) has noted the peculiar condition found in the tail 

 of the Malyan giant hornbill, Bhinoplax vigil, in which but one 

 feather of the central pair is developed at one time. 



* * * and this spike, much longer than the other rectrices, on reaching 

 maturity, remains in position for more than a j'ear, probably for two. Its 

 companion, beginning its growth after the other has gained its extreme length, 

 then equals it in size. The first feather is then molted and is gradually re- 

 placed by another, so that in the renewal of this central pair there is a con- 

 tinual alternation instead of the usual method by which these feathers are 

 renewed synchronously on the right and left sides. 



The facts presented in this paper form only a beginning of what 

 might quite easily be discovered by a careful examination of the 

 countless specimens of birds preserved in the museums of the world. 

 Molt is an important subject in the biology of birds and it is to be 

 hoped that more investigators will pay attention to it, either 

 directly, or in the course of other studies. Dwight's work (6) on 

 the molts of passerine birds, and (7) of gulls should be extended to 

 cover all the various groups of birds of the world. Of fairly recent 

 authors only a few have taken much pains with the subject, but 

 those few writers, such as Stressemann (8) on Eos, Merops, Aplornis, 

 Gramcobius, and other birds of Ceram, and of Bali (11), and of Laub- 

 mann (9, 10) on kingfishers, have found enough points of interest 

 to stimulate further researches. 



LITERATURE CITED 



1. Stone, Witmee. 



The Molting of Birds with Special Reference to the Plumages of the 

 Smaller Land Birds of Eastern North America, Proc. Acad. Nat. 

 Sci. Phila., 1896, p. 114. 



2. Beebe, C. William. 



Preliminary Pheasant Studies. Zoologica, New York, vol. 1, no. 15, 



1914, pp. 263-265. 



S. . 



Notes on the Birds of Par^, Brazil. Zoologica, New York, vol. 2, 



1916, p. 74. 



4. Van Tyne, Josselyn. 



The Life History of the Toucan, Rhampha^tos bremcarinatus. Univ. 

 of Mich., Mus. Zool. Misc. Publ. no. 19, 1929, p. 12. 



5. Wetmoee, Alex. 



A Peculiarity in the Growth of the Tail Feathers of the Giant Hornbill 

 (Rhinoplax vigil). Proc. U, S. Nat. Mus., vol. 47, 1914, pp. 497-500. 

 €. DwiGHT, Jonathan, Jr. 



The Sequence of Plumages and Moults of the Passerine Birds of New 

 York. Annals N. Y. Acad. Sci., vol. 13, 1900, pp. 73-360. 



