Bulletin 



OF THE 



1 iLi.raiRv 



Illinois State Laboratory 



OF 



Natural History 



Urbana, Illinois, U. S. A. 



VOLUME XII 



1915, 1916, 1917 



Contributions to the Natural History Survey of Illinois 

 made under the direction of 



Stephen A. Forbes 



1918. 



c/ 



^ 



