246 Description of a Xeiv Sjjecies of Swift. 



In my list of birds from Yucatan (Ann. N. Y. Lyceum, Vol. 

 IX, p. 204), I referred a specimen of swift to C. Vauxi, though 

 noticing that it was smaller ; now I find it to agree exactly with 

 the bird above described. This comparison I have been en- 

 abled to make, by Mr. Ridgway's kindness in lending me the 

 specimen, and sending besides all in the National Museum that 

 are labelled as C. Vauxi. 



At the time of my examination of the specimen from Yucatan 

 belonging to the Smithsonian, the examples of C. Vauxi ac- 

 cessible were in poor condition ; but since then, fine specimens 

 of it have been received from California, by the National Museum 

 as well as by myself. A comparison with these shows the Yu- 

 catan bird to be quite distinct. 



Among those sent me from Washington, is one specimen from 

 Guatemala (Duenas), collected by Mr. Salvin, Jb'eb. 6th, 1860, 

 and labelled l)y him as C. Vauxi, also one from Mexico (Tehu- 

 antepec), collected by Prof. Sumichrast, which I referred to 

 a Vauxi (Bull. U. S. Nat. Mus., No. 4, p. 32). Both are a 

 little darker than those from Yucatan, but I consider that they 

 are the same. These two specimens have the spines of the tail- 

 feathers in perfect condition, whereas in the two from Yucatan, 

 the spines are worn off close to the tail-feathers ; this abrasion 

 is caused, probably, by their inhabiting rocky cliffs. 



This species differs from C. Vauxi in the much darker color- 

 ing of its upper and under plumage, though in that of the 

 throat they are closely alike ; it is a little smaller, and the 

 Avings and tail are shorter than in C. Vauxi. It has the upper 

 plumag(! blacker even than that of C. i^elasgica, but in that 

 species the under plumage is darker. 



