TREE HOPPERS AND THEIR CONTROL 7 



wings and a hard shell, the pronotum. Viewed from in front they 

 have an odd angular appearance whether they have the pronotal 

 horns (fig. 1, A and C) or no horns (fig. 1, B). The pronounced 

 horns projecting from either side of the pronotum and the large, 

 rounded dorsum are the characteristics which "five the buffalo tree 



Figure 5. — A, Intermingling of oviposition wounds of the green clover tree hopper 

 (a) and the dark-colored tree hopper (6), slightly enlarged; B, colonies of the 

 wooly apple aphid in an old oviposition scar (a), and in a new scar (&), natural 



hopper its name owing to its fancied resemblance to the bison or 

 buffalo. 



The three species most common in orchards of the Pacific North- 

 west may be distinguished as follows: The buffalo tree hopper, 

 Ceresa bubal us (fig. 1, A) is the largest of the three and has pro- 

 jecting pronotal horns. The dark-colored tree hopper, G. basalis (fig. 



