189G.] NATURAL SCIENCES OF PHILADELPHIA. 155 



Petrochelidon lunifrons (Say). ClifT Swallow. 



From such series of this bird as I have examined, I should judge 

 that it had no spring molt ; whether the young molt the flight 

 feathers at the close of the summer I cannot say, as none of my 

 specimens show any molt. 



Chelidon erythrogaster (Bodd.). Barn Swallow. 



The scarcity, in collections, of adults in winter plumage or in the 

 molt prevents a complete account of the molting of this species. I 

 have only one specimen showing the annual molt in progress, which 

 was taken Aug. 7, 1878, at Philadelphia. New feathers are coming in 

 on the breast, throat, and back, and the tail is just beginning to 

 molt. None of the remiges have been cast. Another speci- 

 men, taken Sept. 1 at the some locality, shows a complete molt 

 just finished. As I am not sure whether the young molts its 

 flight feathers with the rest of its first plumage I cannot say whether 

 this is an adult or bird of the year, but my impression is that the 

 young do not molt the wing and tail at this time and that the speci- 

 men is, therefore, an adult. In any case it presents one curious 

 question : The outer rectrices are only .35 in. longer than the next 

 pair (as in all young summer birds). Now all the spring birds that 

 I have examined have the feathers much longer (.75-1.25 in. longer 

 than the next pair), so that there must be a molt of part of the tail 

 at least, in the spring. I do not think there is any spring molt of 

 the wnngs or body feathers. 



Tachycineta bicolor (Yieill.). White-bellied Swallow. 



Plumages : first, winter, nuptial, adult winter. 



Male. — A large series of this species, collected in southern New 

 Jersey illustrates the changes of plumage very satisfactorily. The 

 annual molt in the adults takes place from July 20 to September 1, 

 at which latter date the winter plumage is generally completed. The 

 birds of the year do not begin to molt until the first week of Sep- 

 tember and are in full plumage, indistinguishable from the adults, 

 by October 15. Apparently there is no spring molt, but the white- 

 tips to the wing feathers disappear by abrasion. 



Female. — Two plumages of the female are found, one indistin- 

 guishable from the male, the other much duller and quite brown in 

 the spring. The latter, I think, is the plumage of the first year ; 

 at any rate, in one specimen, it is certainly assumed at the molt of 

 the first plumage. 



