Mr. R. Ridgway nn the Genus Helmiiithophaga. 1G9 



with a concealed patch of orange-rufous (obsolete in young, and 

 sometimes in adult c? also). 



Above gi-eyish, the head sometimes decidedly grey ; beneath pale 

 gi-eenish yellow ; inner web of outer tail-feathers distinctly 

 edged with white. Eastern Province of North America (in- 

 cluding Rocky Mountains) a. cektta. 



Above bright olive-green, below greenish gamboge-yellow ; inner 

 webs of outer tail-feathers without distinct white edges. West- 

 ern Province of North America (Pacific district) . . /3. lutescens. 

 10. H. PEEEGBINA, A diiski/ streak through the eye ; no rufous on 

 the crown ; above olive-green, the head and neck grey ; beneath 

 white {adult), or pale dingy yellow (youm/). Eastern Province 

 of North America. 



Of the foregoing species .only the two recently described 

 admit of any doubt as to their perfect distinctness, all the 

 others having been so long known and thoroughly studied, that 

 all their variations of plumage are familiar. In H. lawrencii 

 the exactly intermediate coloration between H. pinus and H. 

 chrysoptera prompts strong suspicion that the unique example 

 upon which the species is based may be a hybrid between the 

 two ; there are, indeed, only two reasons for giving this theory 

 serious consideration, viz. the very strongly marked and rich 

 coloration, and the reluctance with which we are wont to resort 

 to the belief as to the possibility of hybridism as the real solu- 

 tion of the origin and nature of such intermediate specimens. 

 Should the bird eventually prove to illustrate the stable cha- 

 racters of a distinct species, it will be one of the most remark- 

 able illustrations of the evolution doctrine in the North- 

 American ornis"^. 



The case of H. leucobronchialis is somewhat diflFerent, there 

 being, instead of a combination of the coloration of two 

 species, simply an imperfect development, as it were, of a 



* The combination of the characters of two very distinct and differently 

 coloured species, in this instance, calls to mind several parallel cases, one 

 of which it may be well to mention here. This one is noted iu the 

 'American Sportsman ' for December 12th, 1874 (p. 117), as the capture, 

 by Mr. Christopher D. Wood, of Philadelphia, of a ''black-crested and 

 throated Titmouse, the first one ever heard of." It is there suggested 

 that the bird must be " either a sport or a cross between the common 

 Crested Titmouse (Leophophanes bicolur) and the Black-cap Titmouse 

 {Partes atricapillus)." 



SER. III. VOL. VI. N 



