1^6 Cherrie, A New Ckordeiles fram Costa Rica. \\tX\ 



Chordeiles virginianus aserriensis, 1 subsp. nov. 



Type, No. 4261, collection Geo. K. Cherrie, San Jose, Costa Rica, 

 Nov. 2, 1S93. Smaller and much lighter colored (both above and below) 

 than the true virginianus. Above, grayish predominating; decidedly 

 duskv in center of back where feathers are mostly blackish basallv, tipped 

 and edged with grayish and crossed by irregular broken subterminal 

 bands of the same color. Scapulars blackish basallv, the edges with gray- 

 ish mottlings and buffy blotches. Wing-coverts grayish, finely mottled 

 with dusky. Below, upper breast grayish irregularly barred with narrow 

 blackish bands. Lower breast, sides and flanks lightly huffy whitish 

 regularly barred with blackish, the white and black bands being of about 

 ecpial width. Center of abdomen immaculate white; under tail-coverts 

 slightly buffy, the longer ones showing imperfect blackish bands. 



Length (skin), S.40; wing. 6.96: tail, 4.40. 



This bird agrees with C. v. chapmani in size and in the white 

 unmarked abdomen,- but differs greatly in color above, as it does 

 from a large series of virginianus and from examples of virgin- 

 ianus henryi with which it has been compared. 



The type is a male bird, but the tail does not show the broad 

 white band near the tip found in the males of other species of 

 Chordeiles, but has exactly the same tail as the females. 



Whether this be constant or not, or whether in the male possess- 

 ing a tail marked like that of the female it is a character of imma- 

 turity, I am not in a position to state with certainty. One of the 

 specimens received for examination from the National Museum 3 

 1 No. 128,373, U. S. N. M., Escondido River, Nig., Oct. 28, 1892, 

 Chas. W. Richmond) apparently pertains to this new race. It is 

 a male and has the tail markings similar to those of the type. 

 However, in this example the terminal white band on the third 

 pair of rectrices, from the outside, is wider than on the other 

 feathers. In this specimen the general color above is consid- 

 erably darker than in the type, approaching much nearer to C. 

 virginianus proper. 



1 From the valley of the River Aserri, San Jose, C. R. 



-Comparison is made with the type of chapmani, recently acquired by the 

 Field Museum as a donation from Prof. C. B. Cory. 



:i I am indebted to the authorities of the Smithsonian Institution and to those 

 of the American Museum of Natural History for the loan of specimens used 

 in the preparation of this paper. 



