LETTER OF TRANSMITTAL. 
CampripGe, Mass., April 3, 1876. 
Str: I transmit herewith for publication my report. on the North Amer- 
ican Leporide. As but two species of this family occur south of the United 
States that are not also found north of the United States and Mexican boundary, 
these have also been included, thereby rendering the present memoir a mono- 
graph of the Leporide of the New World. 
The material on which this report is based is primarily that of the 
National Museum, to which, through the kindness of the officers of the Smith- 
sonian Institution, I have had the fullest access. This has been supplemented — 
by that of the other principal collections of this country, by far the most 
important of which is that of the Museum of Comparative Zodlogy, Cam- 
bridge, Mass., of which also I have been permitted the freest use. 
It gives me pleasure to mention in this connection that a large part of 
the material from the Trans-Mississippian portions of the United States has 
been gathered either personally by yourself or under your immediate direction 
and auspices. 
Tam, sir, very respectfully, yours, 
J. A. ALLEN. 
Dr F. V. Haypen, 
United States G'cologist, etc., etc., Washington, D. C. 
