280 SNODGRASS AND HELLER 



areas of the feathers darker. Wing and tail feathers dark brown with 

 olive-buffy edgings. 



There is considerable variation in the color of the adult females. 

 Some are, as described above, almost exactly the same as the males, 

 but others have the lower parts plain buff -gray with no spots whatever. 



Immature Males and Females. Feathers of the head and back 

 with blackish centers and olive-yellowish borders, on the head the 

 black predominates, on the rump the olive-yellow, on the back the 

 two are present in almost equal proportions. Wing and tail dark 

 brown with buff edgings to the feathers ; these edgings are widest and 

 most conspicuous on the tips of the greater and middle wing coverts. 

 Under parts similar to the adult male, having the same spots, but 

 generally paler. Bill dusky or brownish above, pale brown or yel- 

 low below. Feet dark brown. 



Still younger birds (represented only by males in our collection) 

 are colored like the last but have no spots on the under surface, being 

 plain dirty grayish below with a buff tinge, especially on the breast 

 and along the sides. 



We have no females of this stage but it is to be supposed from 

 analogy that they do not differ from the males. 



The extent of the olive coloring on the upper parts varies according 

 to the abrasion of the plumage. We have no specimens of this species 

 in the purely olive and yellow plumage characteristic of Stage I, but 

 since this plumage is well represented by G. pallida we may expect 

 to find it present in G. heliobates. 



Rothschild and Hartert * make the following remark concerning 

 Geospiza pallida: "The birds which are olive and bufRsh yellow 

 below are immature ones, but it is somewhat puzzling to account for 

 the distinct blackish brown stripes on the lower throat, chest and sides 

 of the body in some of them. Neither the apparently most adult 

 ones, nor the most yellowish, and therefore, according to our view, 

 youngest of the series, have these stripes well developed." The facts 

 of the case are as follows (applicable to either species of the subgenus) : 

 (i) The youngest birds of each sex are unspotted below ; (2) older 

 immature birds of both sexes have the lower parts profusely spotted, 

 in some cases even more so than in the adults ; (3) adult males are 

 generally more or less spotted below ; (4) adult females may be 

 spotted below or they may be entirely plain there. The apparent in- 

 congruity pointed out by Rothschild and Hartert of some of the females 

 losing their spots in maturity may be explained as follows : The indi- 



1 Novitates Zoologicae, vi, p. 166, 1899. 



