ORNITHOLOGICAL EXPLORATIONS. 133 



in color, distinguishable in all plumages, adults and young, summer 

 and winter specimens. 



The reason why Cassin failed to maintain the distinction between the 

 two species was partly that he overlooked the structural differences, 

 partly that he mistook the adult barred suuimi-r plumage for that of 

 the young, while it is the young i>lumage which he regarded as the 

 breeding dress. 



If the ornithologists interested in this question will place before 

 them their specimens, or series of specimens, I would propose to 

 them to measure the length of the nasal groove from the loral apex of 

 the feathering to the foremost end of the furrow. Specimens in which 

 the groove is as long as about two-thirds of the length of the exposed 

 culmen from the feathering, belong to Eeteractitis incanus; specimens 

 in which this groove is only half as long as the exposed culmen are true 

 ff. brevipes. If the collection is large enough we will find, when dividing 

 it into two series, according to the above character, that each of these 

 contain specimens, some of which are distinctly barred underneath, 

 partially or wholly, others being only more or less uniformly clouded 

 with gray on fore neck, throat, and flanks. If now comparing the, 

 barred specimens of both series, we will find the following differences in 

 color : In those with the long nasal groove, incanus, the whole under 

 surface, including middle of abdomen and under tail-coverts, is dis- 

 tinctly and uniformly barred with blackish gray, and the back is purer 

 gray ; in the specimens with the short groove the middle of the abdo- 

 men and the under tail-coverts are pure white, the dark bars on the 

 other x>art being lighter and finer, while the back is more tinged with 

 brownish. Upon taking measurements we will find that the long- 

 grooved, heavy-barred incanus average larger than the short-grooved, 

 lighter brevipes. 



If we now compare the two series of unbarred specimens we will 

 find that the long-grooved ones are purer gray and average larger 

 (incamis) than the short-grooved ones, which are api^reciably browner 

 and smaller. 



Anybody taking the trouble of still closer examining his specimens 

 will soon find additional characters, and will especially appreciate the 

 distinct and regular white bars — two or more on each feather— on the 

 upper tail-coverts of the^unabraded plumage, in brevipes, in contradis- 

 tinction to those in incanus, in which these feathers are either uniform 

 gray or with a very narrow light edging. 



