4 
Mr. R, Ridgway on the Genus Helminthophaga. 169 
with a concealed patch of orange-rufous (obsolete in young, and 
sometimes in adult ¢ also). 
Above greyish, the head sometimes decidedly grey; beneath pale 
greenish yellow; inner web of outer tail-feathers distinctly 
edged with white. Eastern Province of North America (in- 
eluding Trocky Nouittaine ies fates ees aes se ces a. celata. 
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) .. 8. lutescens. 
10. H. prreerina. A dusky streak through the eye; no rufous on 
the crown ; above olive-green, the head and neck grey; beneath 
white (adult), or pale dingy yellow (young). 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 different, 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 in 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 bicolor) and the Black-cap Titmouse 
(Parus atricapillus).”’ 
SER. II1I.—VOL. VI. N 







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