Maynard.] 378 [October 18 ; 



cies. This is especially noticeable in the Fly-catchers, specimens 

 from the south being very much browner than those taken north. 

 In making these observations, the student will also perceive that spe- 

 cies having stripes or spots caused by dark centres of the feathers, 

 are subject to wide individual variations in this respect. In speci- 

 mens with generally pale colors 1 the lighter margin of the spotted 

 feathers will be wider, and if the central stripes are narrow or the 

 spots small, the entire feathers will become of a uniform color, or 

 with a shade or two darker nearer the base. In darker colored indi- 

 viduals the reverse is the case, the darker spots become larger and 

 increase in number. This is particularly to be remarked in the gen- 

 era of Turdus, Myiarchus and Empidonax. 



Again, in pale specimens all white markings, such as bars on the 

 wings, terminal spots on the quills or tail feathers, generally increase 

 in size and width, while in the darker types these spots and bars will 

 decrease and sometimes disappear entirely. 



Another character which is considered of specific value in compar- 

 ing these supposed species, is the number of the longest quill and 

 its comparative length. To show how inconstant this is, we have 

 but to examine a series of any of the Fly-catchers. Take for exam- 

 ple E. minimus, and of 23 specimens examined, 12 have the third 

 quill the longest, 3 the second, 7 the second and third, while one has 

 the fourth. 



Understanding, then, the slight, though constant, difference be- 

 tween minimus and Traillii, it seems to me that, with the individual 

 variations to which these species are subject, it is impossible to form 

 a single species between them with constant characters not possessed 

 by either one or the other, but when two are brought forward, and 

 characters sought after that are strictly specific, dividing each from 

 the other, and both from Traillii and minimus, the subject becomes 

 very much confused, and exceedingly difficult to comprehend. 



91. Empidonax flaviventris Baird. Yellow-bellied Fly- 

 catcher. 



" Common at Franconia, where it breeds. I have seen the young 

 out of the nest by August 1st. When the young were approached 

 the female uttered the usual pea as a note of distress, but more plain- 

 tively than at other times. Frequents the maple undergrowth in the 

 mountain ranges " (Brewster). Not uncommon at Umbagog. Prob- 



1 Represented in dark brown colors by a bright rufus, in rufus by buff, in dark 

 olive or brownisb green by brighter greens, or more olivaceous. 



