THE LOCUST OF THE SEVENTEENTH YEAR. 461 



and is the remains of the female, who shelters the 

 eggs which are placed beneath it. These eggs vary 

 in number from twenty to one hundred, according 

 to the health of the tree. Those which are the 

 most vigorous have the greatest number. About the 

 middle of May the eggs begin to hatch, and the 

 larva to run about. It is pale yellow in color, has 

 three pairs of legs, and appears upon the wood only 

 as a minute dot. It has an enemy in a maggot which 

 finds shelter beneath the scale, and feeds upon the 

 eggs. This louse seems to be advancing westward, 

 and is particularly injurious in the new districts, 

 probably because it does not meet so many enemies. 



Two methods of destroying it are practised ; in 

 one, the trees are thoroughly painted in early spring 

 with tar and linseed oil, heated together, and applied 

 warm. When this becomes dry it peels off, bring- 

 ing the scale with it. In the other method, tobacco- 

 leaf is boiled in strong lye until it is reduced to an 

 impalpable pulp, and soft soap is mixed with it to 

 make the mass about the consistency of thin paint ; 

 the object being to obtain a preparation which will 

 not be washed off by the first rain. The trees are 

 first cut in, and the mixture applied with a paint- 

 brush to every twig. This will destroy the insect, 

 or prevent the deposition of eggs for the next 

 season, so that an application once in two years will 

 suffice (Fitch). 



(6) The effusion of sap caused hy the puncture of the 

 39* 



