1896.] NATURAL SCIENCES OF PHILADELPHIA. 131 



does not produce much effect upon the plumage but it loses the 

 bright metallic luster which characterizes the fresh winter dress. 

 I am inclined to think that the young do not renew the flight 

 feathers at their first molt. 



Family TROCHILIDJE. 



Trochilus colubris (Linn.). Ruby-throated Humming-bird. 



The only molting specimens of the Humming-bird that I have 

 seen are spring birds taken at Labna, Yucatan, March 15th, in 

 which the feathers on the throat are being renewed. Probably, tlie 

 young males acquire the ruby throat at this time. 



Family TYRANNIC^. 



The Tyrant Flycatchers show scarcely any seasonal variation, the 

 first plumage being nearly the same as the adult, while the feathers 

 are very little affected by abrasion. There are, therefore, as a rule 

 only three plumages ; first, winter and nuptial. 



Tyrannus tyrannus (Linn.). Kingbird. 



Adult Kingbirds, taken August 21, show some molt on the 

 body but no trace of renewal of the flight feathers, which would 

 indicate that the annual molt is not completed until quite late. 

 Some spring specimens show a few new feathers appearing on the 

 breast and back, but whether there is a more extensive renewal of 

 the plurbage before the birds start north from their winter quarters 

 I cannot say. Abrasion plays little or no part in changing the 

 plumage of this species. The first plumage gives way to that of the 

 adult late in August but no molt occurs in the wing and tail. 



Myiarchus crinitus (Linn.). Crested Flycatcher. 



The annual molt in this species begins early in August and is 

 indicated in the wings before any new feathers appear on the body, 

 differing in this respect from the last. There seems to be no spring 

 molt. The young birds of the first brood begin to renew their body 

 plumage early in August. All the plumages of this bird are very 

 similar. 



Sayornis phoebe (Lath.). Pewec. 



There is no spring molt in the Pewee but much abrasion takes 

 place during winter so that the sulphur tint of the under surface, 

 which is characteristic of fall specimens, is nearly lost by the breed- 

 ing season. The molt of first plumage in the young is restricted to 

 the body feathers. 



