222 BULLETIN OF THE 



same way, as do those of (he king-bird. Similar and nearly as great 

 variations occur also between different specimens of Contopus borealis, 

 C. virens, Empidonax minimus, E. jiaviventris, Sayorius fuscus, and 

 in several species of (he South American Tyrannida. But between 

 these (wo extremes are found in other specimens nearly every possible 

 degree of gradation. 



Figures 3 and oa to figures 7 and la (same plate) represent different 

 forms of the bill in Troglodytesaedon. Between these specimens there 

 are great differences both in respect to absolute size and to general 

 form, greater than would be deemed necessary by most ornithologists 

 for the differentiation of species. These examples are all from Florida, 

 and essentially from the same locality. Other specimens in the Muse- 

 um come between these extremes in such a way as to show the incon- 

 stancy of all these forms. The variation in color, which is considerable 

 in this species, does not accord with the variation in the bill, specimens 

 exhibiting the extremes of color as often having the bills alike as other- 

 wise, and, conversely, those with bills alike differ widely in color. 



Figures 8 and 8a to 11 and 11a (same plate) indicate the varia- 

 bility of the bill, especially in respect to length, in Massachusetts 

 specimens of Seiurus noveboracensis. The first corresponds essentially 

 with, and unquestionably is, an example of the so-called Seiurus ludo- 

 vicianus, which, in all probability, is but the darker colored, longer- 

 billed southern form of S. noveboracensis. This species varies also 

 remarkably in color, but the variation in color, as in the case of Tro- 

 glodytes aedon, and as is commonly the case in other species, does not 

 accord with the variation in the bill, some of the long-billed specimens 

 being in color almost undi-tinguishable from some of the short-billed 

 ones, while some of those with medium bills present the extreme 

 degrees of variation in respect to color. 



Figures 12 and 12a to14 and 14a (same plate) represent the bills 

 of three, male specimens of Mniotilta varia from the vicinity of Cam- 

 bridge, which present as great differences as modern ornithologists 

 would ordinarily deem sufficient, if the specimens had come from 

 Mexico instead of from Massachusetts, to warrant their recognition as 

 types of three distinct species. The correspondingly great variations in 

 color in this species have already been adverted to (p. 190). The 

 bill, however, in specimens presenting extreme forms of color variation, 

 unfortunately for ultra-divisionists, may be either of the ordinary form 



