Bui. 118, U. S. Dept. of Agriculture. 



Plate IV. 



CC r~ 



2 -75 



•^ - SO 



co -*0 



cc >.^-' 



O » 



z gj 



X CD 



cc >c w 



< >>& 



-J ££ 



ti! 3 a 



z g3 



O ■" be 



O o3 O 

 CC rj 



Q " 



