SMITHSONIAN MISCELLANEOUS COLLECTIONS. 



171 



MONOGRAPHS 



D I P T E R A 



NORTH AMERICA. 



PREPARED FOR THE SMITHSONIAN INSTITUTION 

 BY 



H. LOEW. 



PART II 



EDITED BY 



R. OSTEN SACKEN 



WASHINGTON: 

 SMITHSONIAN INSTITUTION. 



JANUARY, 1864. 



