00 BLACK SNOW BIRD. 



is governed by a Y-shaped muscle, seen at i, d, and at e, where 

 it is greatly enlarged. For other peculiarities we find that al- 

 though the bronchialis, and broncho trachealis are fused to- 

 gether in a great measure (see c and b) they are divided below 

 the point of the insertion of the sterno-trachealis, ib. s. The 

 transverse bone, a, is present, and although it supports a 

 small semiluna membrane, it is so fixed that it cannot be os- 

 cilated. In order to understand these variations, fig. 6 should 

 be compared with figs. 7 and 8 on page 7. 



Genus SNOW BIRDS. Junco. 



Small birds, not over seven inches long. Slaty gray in 

 color above, with the outer tail feathers conspicuously marked 

 with white. Bill rather slender and pointed. Wings, a little 

 longer than the slightly forked tail. We have one species, 

 with sexes somewhat dissimilar, and no prominent wing bars. 



Black Snow Bird. 



Junco hyemalis. 

 Plate XIV, Fig. 1. 



Dark slate throughout, excepting onlower breast, abdomen, 

 greater portion of two pairs of outer tail feathers and a spot 

 on the third pair, which are white. Bill, pinkish. Female, 

 similar, but paler slate, which is more or less obscured by 

 reddish. Winter birds and young are also quite strongly 

 tinged with reddish. Nestlings are thickly streaked above and 

 below with dusky. 



Dimensions. Length, 6.25; stretch, 9.80; wing, 8.00 ; 

 tail, 2.60; bill. .42; tarsus, .75. 



