Bui. 834, U. S. Dept. of Agriculture. 



PLATE I 



The Black Grain-Stem Sawfly of Europe in the United States. 



A, Tracheitis tabidus: Lateral view of apical segments of larva; B, Cephus cinctus: 

 Late-al view of apical segments of larva; C, Cephus pygmaeus: Lateral view of apical 

 segments of larva. 



