522 The American Naturalist. [June, 
were sent out by the National Museum, and the matter 
received in reply was turned over to me for study and investi- 
gation, together with the privilege of preparing the results for 
publication. 
UNITED STATES NATIONAL MUSEUM 
DER DIRECTION OF 
THE SMITHSONIAN INSTITUTION. 
Dear Sir: 
The National Museum is engaged in a systematic investigation of the color- 
hases of the Screech Owl ( Megascops asio), with the view of determining the relative 
abundance of the red and gray plumages in different parts of the country, the plu- 
mage of the young, produced by parents of known character as to plumage, and the 
other related questions. 
rder that the investigation may be as thorough as possible, assistance in 
the matter is requested; and if you can give information on the subject, your kind 
co-operation will be much appreciated. 
Should you favor us with any information on the subject, please arrange the 
data in the following order: 
ame your locality, including County and State. 
(2) State about how many specimens have come under your notice, and how 
many of them were in the gray plumage. 
(3) If you have obtained or observed a pair of old birds with their young, state 
the character of plumage of the former (whether both red, both gray, or one red an 
one gray—and if the latter, the sex represented by each phase), and also the plumage 
of the young. 
The above are the principal points upon which information is desired, but any 
additional memoranda will be very acceptable. 
ours truly, 
ROBERT RIDGWAY, 
Curator, Department of Birds. 
In conclusion I wish to express my gratitude to Professor 
G. Brown Goode, Assist. Secretary of the Smithsonian, and 
Mr. Robert Ridgway, Curator of Birds, who rendered every 
assistance and courtesy in their power; while to all who 
responded to the request for information, without which the 
task would have been impossible, is due the sincere thans 
of The Author 
Part I. 
RELATIONSHIP OF DICHROMATISM TO EVOLUTION, 
So universally adopted has the theory of evolution become, — 
that it scarcely seems necessary to refer to it as forming thé 
Ste ee eee ee a 
ep ee ae all) Rete 
