224 DWIGHT 



for with the exception of T. bicolor, they migrate southward in 

 the autumn before acquiring their winter dress, so that a mere 

 handful among hundreds of specimens examined, show signs of 

 moult before they have passed beyond the borders of the United 

 States. A few specimens from Mexico and Central America 

 show that both adults and young birds reach these countries in 

 worn nuptial and worn Juvenal plumages respectively and two or 

 three more afford evidence of a mid-winter moult, the occurrence 

 of which has been previously affirmed by other observers. 



From these meagre facts and from the study of the feathers, 

 which, on account of the metallic colors and the aerial habits 

 of the Swallows, show little evidence of wear, we may not 

 draw positive conclusions, but two at least may be reached with 

 considerable certainty. The first is that adult Swallows undergo 

 a complete postnuptial moult late in the fall, either while on 

 their southward journey or at its conclusion ; and the second is 

 that young Swallows undergo a complete postjuvenal moult (or 

 prenuptial perhaps in point of time) later than the postnuptial of 

 the adult. More specimens are needed to fix the limits of these 

 two moults, but I am of opinion that mid-winter birds in moult 

 will all prove to be young ones. It may perhaps be expedient 

 to call this a prenuptial moult and consider the postjuvenal sup- 

 pressed, but this is only a matter of convenience and would not 

 alter the facts nor disturb my scheme of plumages and moults 

 which has been devised so as to give clear expression to the 

 facts. These may be found discussed under each species, and I 

 hope a much larger fund of material may accumulate within a 

 few years now that I have pointed out the deficiencies in that at 

 present available for study. 



Progne subis (Linn.). PURPLE MARTIN 



1. NATAL DOWN. No specimen seen. 



2. JUVENAL PLUMAGE acquired by a complete postnatal moult. 



Above, including wings and tail, sooty or clove-brown, the forehead and a nuchal 

 band grayish, the feathers of the head and back indistinctly dull steel- 

 blue. Feathers of the wings with very narrow whitish edgings. Below, white, 

 mouse-gray on chin, throat, breast, sides and tibine, the feathers of the chin, 



