164 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[164 



o 

 u 



a 

 o 



oo 



CO 



CM 



co 



oo m 

 o <p 



H * 





CQ 



cS 

 +^ 

 o 

 P! 

 ps 

 ft 



s 



o 



+j 



>> 



s 

 s 



