AMERICAX WARBLERS. 8.5 



tend along the web to its termination, but this may have been a mark oi compara- 

 tive immaturity. I also find that in quite a number of specimens of this species the 

 white crosses the vein and occupies an elongated space on the inner web, and this 

 may be a mark of high maturity. Both sexes in both species share alike in these 

 markings. 



When I learned the facts related it at once occurred tome that this test regard- 

 ing the spois on the tail feathers applied to both Brewster's and Lawrence's Warblers 

 might, in a measure, settle the vexed question of their specific status. As far as 

 Brewster's Warbler was concerned, all examined were like the typical Golden-wing 

 and had a small, dark space on the inner web of the second tail feather. But when 

 I came to apply the test to the only two apparently adult specimens of Lawrence's 

 W'arbler in the collection, one was like the Golden-wing and one like the the Blue- 

 wing. A half dozen younger birds agreed with the Golden-wing in having the dark 

 space at the terminaton of the vein. Thus far, then, the evidence shows ihat the 

 tail coloration of the greater number of both Brewster's and Lawrence's Warblers is 

 similar to that of the Golden-wings, for an examination of a mere extended series 

 would doubtless show that the single exception to the rule, noted above, will prove 

 only one of a very small per cent that exhibit the extreme in individual variation. 



Now lookingatthe question regarding the status of both Brewster's and Law- 

 fence's Warblers broadly, guided by the facts as they are presented to us, I do not 

 see how we can avoid the conclusion that I have given, and not consider both of these 

 birds incipient spe ies ^^hich have been evolved from the Golden-winged Warbler as 

 related above. We will return toa further consideration of this theory after discuss- 

 ing the two points mentioned. 



First let us examine Mr. Brewster's theory. We will begin by counting the 

 points in favor of this theory of hybridization, and it must be admitted that, at first 

 sight, there ap-pear to be some good ones. 



First and most important, is color. Both Brewster's and Lawrence's, but more 

 especially the former named, show, according to my observations, supplemented by 

 Mr. Brew.-ter's, as quoted, gradations between the Blue-winged and Golden-winged, 

 and consequent'y Brewster's and Lawrence's appear to intergrade with one another as 

 well. 



Second, there is published evidence which tends to show (unless mistakes 

 have been made) that at least three of the forms, namely the Golded-winged, Blue- 

 winged and Brewster's mate together. 



Third, the supposed hybrids occur mostly in sections where the Blue-wings 

 and Golden-wings overlap during the breeding season. 



Fourth, Brewster's Warbler is said to sing sometimes like the Golden-wing, 

 sometimes like the Blue-wing and sometimes a song of its own, thus differing from 

 both of the others. 



Takingthe first point into consideration, we find that, although at first sight 

 there may be apparently complete intergradation, yet there are some things that are 

 difficult to explain by the theory of hybridization. Why do wc not find many exam- 

 ples of I ndoubfed Brewster's Warblers with an indicaticn of the dark throat pa'ch 

 of the Golden-wing. I do not know what num! er liave been seen bv Mr Brewster, 

 but his own seiies does not show any, and Mr. Ridgeway, in his late work (Birds of 

 North end Middle America, Fart 11, p. 455), speaking of Brewster's Warbler, dis- 



