1893.] Evolution in the Genus Megascops. 525 
absent, while at the southern limit it is greatly in the major- 
ity? These and many other questions of equal importance 
present themselves, and but confuse and leave the reader 
more than ever in the dark. 
While collecting screech owls in the District of Columbia 
during the winter of 1890-91, these questions arose very forci- 
bly, and upon investigating, I found that while the matter 
was apparently settled to the satisfaction of ornithologists, as 
regards the identity of the two forms, nothing further 
appeared to be known aboutit. Further investigation showed 
that dichromatism is principally confined to the typical form 
of Megascops asio, appearing but slightly in the Florida form 
(Megascops a. floridanus), and barely reaching the Texan sub- 
species, mccallii. The remaining members of the group, four 
in number, remaining true to their normal color. 
Three phases of plumage were clearly defined—the red, the 
gray, and the intermediate (the last less frequently seen than 
the others). Three distinct phases, represented indiscrimi- 
nately by individuals of one-species, regardless of age, sex or 
season! Such an unusual circumstance that the possibility of 
some great and important change gradually taking place at 
once suggested itself, which has been proved to be in reality 
the case. 
An attempt will be made to show, first, that while the red, 
the gray and the intermediate phases are at present but indi- 
vidual variations of the same species—the gray was the ances- 
tral stock ; second, that from the gray bird has evolved the 
red, which at some future time will be a recognized sub-spe- 
cies with a range peculiar to itself, and thus dichromatism 1s 
one step in the evolution of the Screech Owl, while the vari- 
ous phases exhibited are the transitorial stages of develop- 
ment of one species from another; third, that this condition of 
affairs is influenced by four powerful factors (two of which 
; sub-speci ibed by Brewster (Auk, Vol. VIII, 1891, 139- 
1) wel make piorar para aipha are al yet admitted to the check 
EAT a lennie exkibits a dict tic phase, but it is a decided dark brown, and 
“Rot a reddish phase, and is not included in the present treatise. ' 
35 
