UNITED STATES DEPARTMENT OF AGRICULTURE 
LIBRARY 
WASHINGTON, D. C. 
IN YOUR REPLY PLEASE REFER 
TO NUMBER 
April 3, 1930. 
Library, 
Museum of Comparative Zoology, 
Harvard University, 
Cambridge, Mass. 
Dear Sirs: 
We are returning by registered mail Clark's Essay on the Bots of 
Horses, which you were kind enough to lend us. Our own copy was incom¬ 
plete and we have taken the liberty of photostating from your copy the 
missing pages. We are sending you, inclosed, a photostat copy of a 
"Supplementary Sheet" of four pages which is bound up in our copy but 
not in yours, and which we thought you would like to have if it is not 
already in your Library. Please accept our thanks for the loan. 
Very truly yours. 
Acting Librarian. 
ebh:g 
