INJURING THE BRANCHES. 145 



But the females remain upon the leaves until nearly 

 time for them to fall in autumn, when they desert 

 them and migrate to the twigs, attaching themselves 

 by inserting their beaks into the bark. Here they 

 remain until the following season, the eggs grad- 

 ually developing and being deposited during spring. 

 These insects sometimes do great damage to maple 

 trees. They excrete or secrete a peculiar liquid 

 which falls upon the leaves, and the ground beneath 

 the trees, which is sometimes called ' honey dew.' 

 There are a large number of parasitic and predace- 

 ous insects that prey upon this species, and suppress 

 its periodical uprisings. 



Remedies. — In cities where a stream of water 

 from hose connected with water-works is available, 

 the trees can be largely cleared of the pests by re- 

 peated drenchings. In the spring before the eggs 

 hatch, and also while the young lice are crawling 

 over the tree, soon after hatching, is the best time for 

 this work. The young lice may also be easily de- 

 stroyed by spraying with kerosene emulsion. This 

 should be done in June, soon after they hatch. 



The Box-elder Bug. 



Leptocor is trivittatus. 

 In the region west of the Missouri river this insect 

 is extremely abundant, causing serious injury to the 

 Box-elder, and occasionally, also, to ash, maple, and 

 other trees. The adult (Fig. 73) is a dull black bug 

 about half an inch long, having blood red ocelli, and 



