HEMIPTERA. 



I6 5 



caused many species that infest cultivated plants to become 

 world-wide in distribution. 



During recent years much attention has been paid to 

 devising methods of destroying these pests. Various soapy 



FIG. 202. The Scurfy Bark-louse. Chionaspis furfunis : i, scales natural size; i, 

 scale of male enlarged ; i, adult male enlarged ; ic, scale of female enlarged. 



or alkaline washes, and one made of lime, salt, and sulphur, are 

 now used on the trees with deciduous foliage; the wash is 

 applied during the winter while the trees are naked. In the 

 case of orange and lemon trees, which are constantly clothed 

 with leaves, a large tent is lowered over the tree and a 



