312 FIELD MUSEUM OF NATURAL HISTORY ORNITHOLOGY, VOL. I. 



4. That the extent, shape and size of the black spots on the under 

 parts in males from the same region evidently vary in individuals of 

 practically the same age, and while in some cases they apparently show 

 decided diminution in the adult, in others they are much more persistent. 

 In the series before me, old males of C. s, cinnamomina and C. s. australis 

 have the spots much smaller, narrower, and confined to the sides and 

 upper abdomen, the lower abdomen and flanks being immaculate. In 

 the young the spots are much larger and extend upon the lower abdomen 

 and flanks. In C. s. brevipennis, however, (and probably other closely 

 allied forms) very young males have the lower breast and practically the 

 whole of the abdomen heavily spotted with black, while in old males 

 the under parts appear to be nearly immaculate, the black spots being 

 largely or wholly confined to the flanks and sides of the body. It is also 

 evident, at least in some of the South American forms, that the presence 

 or absence of rufous on the crown and the extent of the black spots on the 

 under parts are not correlated, as for example, in the series of 20 males 

 from Chapada, Matto Grosso, and Bahia, none of the specimens 

 showing rufous on the crown differ very appreciably in the amount 

 of black spotting on the under parts from those having the crown clear 

 gray. 



5. That the variation in coloration and marking of the outer rectrix 

 is very great in specimens from some regions, but decidedly less so from 

 others; and while the instability of this character apparently renders it 

 by itself of little or no diagnostic value, it seems desirable that in regions 

 where deviation from the general type appears to be the exception it 

 should be taken into consideration in connection with other differences 

 in distinguishing subspecies, if for no other reason than to enable future 

 investigators to draw their own conclusions. 



As an illustration of this, in the series before me 28 males from 

 Colombia and western Venezuela show great variation in the coloration 

 and pattern of the inner web of the outer rectrix: in some it is largely 

 rufous; in others black and white without rufous; and again part white 

 and part rufous, sometimes with one and again with several black bars. 

 Under such conditions such a character would be obviously useless in 

 diagnosis. In fact in some individuals the outer rectrix on opposite 

 sides of the tail is differently colored in the same bird. This is at least 

 suggestive, and as the weight of evidence appears to prove that this per- 

 plexing variation in coloration is not due to age,* it would seem not un- 

 likely that it might be largely the result of intergradation in regions 



* Specimens which I have examined show that, with the exception of a rusty 

 tinge on the tip, the coloration of the outer rectrix is normally the same in young 

 and old birds of C. s. patilus and C. s. brevipennis. See also, Hartert, Nov. Zo6l., 

 1898, p. 501. 



