OMMISSION 





A PRELIMINARY REPORT 



ON 



Aquatic Invertebrate Fauna of the Yellowstone 



National Park, Wyoming, and of the 



Flatliead Region of Montana. 



S. A. FORBES, 



I'KOH H ILLINOIS. 



.1 |>iil,lir:ilim,. April 'J'.l 



\SHTNGTO 



no v i 



1 s 



BY 

 F 



