160 FRUIT INSECTS 



As there is danger that nursery trees may become infested by • | 

 migrants from elm, it is not advisable to allow these trees to * 

 grow in the vicinity of the nursery or to grow elm stock with 

 apple stock in the same nursery. 



References 



Mo. Agr. Exp. Sta. Bull. 35. 1896. 



U. S. Bur. Ent. Circular 20. 1897. 



U. S. Bur. Ent. Bull. 18, pp. 78-81. 1898. 



Ga. State Bd. Ent. Bull. 23. 1907. 



Col. Agr. Exp. Sta. Bull. 133, pp. 5-23. 1908. 



Me. Agr. Exp. Sta. Bull. 203. 1912. 



U. S. Bur. Ent. Circular 158. 1912. 



Me. Agr. Exp. Sta. Bull. 217. 1913. 



Me. Agr. Exp. Sta. Bull. 220. 1913. 



The Buffalo Tree-hopper 



Ceresa bubalus Fabricius 



Young fruit trees in the upper Mississippi Valley and east- 

 ward through the United States and Canada to Nova Scotia 

 are often seriously injured by this curious little grass-green, 

 triangular-shaped, active bug, about f of an inch long, with 

 large, horn-like projections of the anterior angles of the thorax 

 which give it a fancied resemblance to a male buffalo, hence 

 its common name (Fig. 167). The injury is all done by the fe- 

 male bugs in laying their eggs from July till October in the bark 

 on the upper sides of the smaller branches. Two slightly curved 

 slits about ^ of an inch long are made near together in such 

 a way that the bark between the incisions is cut loose. From 

 6 to 12 long, cylindrical, whitish eggs are stuck into each slit 

 and do not hatch until the following May or June. These 

 peculiar egg-scars rarely heal and gradually enlarge, giving the 

 branches a very rough and scabby appearance (Fig. 167a). Two- 

 or three-year-old apple and pear trees usually suffer most, but 



