VOL, XIV 

 1891. 



] PROCEEDINGS OF THE NATIONAL MUSEUM. 345 



the bend of the wing is not so decidedly orange, and below the sides 

 and flanks are grayish brown with a faint shade of olive. Another 

 Nicaragnan bird has the superciliaries almost as grayish as Pacific 

 Coast birds and the back almost as bright. A specimen from Aspin- 

 wall has the superciliaries grayish posteriorly; the back as bright as 

 Panama examples, bat the sides and flanks are more brownish gray. 



Thus while it will be seen that the Atlantic and Pacific forms can 

 hardly be separated b^' hard and fast lines, yet the Atlantic form seems 

 always separable, having white superciliaries, a darker back, a darker 

 yellow bend to the wing (orange, not lemon), the sides, flanks, and 

 under tail-coverts more brownish and less grayish. While some of 

 these characters may fail, all will scarcely fail in the same bird ; and the 

 darkest or typical birds from the Atlantic side differ so decidedly from 

 typical examples of the Pacific form that I am loath to class them as 

 one bird. Accordingly in case a larger series of specimens may prove 

 the differences constant as they seem, I would suggest the name 

 Arremon aurantiirostyis saturatus for the dark-colored bird found on 

 the Atlantic side. 



Myrmeciza intermedia, sp. uov. 



An examination of the allied forms of .l/j/rmec»crt, including my re- 

 cently described occklentalis (Auk,, vii, April, 1S91), has led me to 

 conclude that Costa Eica has yet another form allied to imwiftcw/rtYa, 

 the habitat of which extends from the southeastern coast region of 

 Costa Rica (Talamanca) to Panama. For this apparently new form I 

 have chosen the name intermedia. 



Adult male (Type, No. 64715, U. S. National Museum, Sipurio, Tal- 

 amanca, Costa Rica, April 8, 1873, J. C. Zeledon). Similar to immaculata, 

 but having the under primaiy-coverts concolorwith the quills, and the 

 first primary only faintly, if at all, edged with white. Just a trifle 

 smaller. 



In the original description of immaculata (P. Z. S., 18G4, p. 357) no 

 mention is made of the color of the under wing coverts, nor of the 

 white edging to the first primary, only saying " campterii margine albo.'^ 

 However, as examples with the first primary distinctly edged with 

 white (as well as the alula) and the under primary-coverts white, 

 tipped with ashy, do not seem to extend north of the Talamanca coast 

 of Costa Rica, and as the type came from Panama, I take it as probable 

 that it is this form (with white under primary-coverts) that is referred to. 



31. intermedia extends from Panama along the Atlantic lowlands in 

 Costa Eica to Nicaragua. It was, of course, with this form that I made 

 my comparisons in describing occidentalism the males of which differ but 

 slightly from those of intermedia, while the females are quite distinct. 

 Unfortunately we have no authentic females of immaculata. 



M. exsul seems to differ from the three more northern forms in having 

 the inner edges of the reraiges ashy whitish, and in being much lighter 



