150 Control of Parasites 



I. Bugs, comprising a number of insect families sep- 

 arated in strict classification into Hemiplera (half-wings, 

 partly leathery), Orthoptera (straight wings, membra- 

 naceous), etc. 



Here belong the various plant-lice, bark-lice, root-lice, 

 mealy bugs and scale-insects, also tree-hoppers, grass- 

 hoppers, and cicadas; a large number of species, on the 

 whole but slightly injurious to tree life; besides some of 

 those most destructive to crops, like the chinch-bug, cab- 

 bage-bug, squash-bug, etc. 



Their mischief consists in sucking the sap and sometimes 

 causing gall-like malformations of relatively little moment, 

 although they can, if excessively developed, cause the death 

 of limbs and even of trees. 



Plant-lice have green to greenish-black, flask-shaped 

 bodies, covered with a soft, powdery bloom or wool, winged 

 or unwinged; wintering in the egg; hatching as vegetation 

 begins and producing four to nine generations during the 

 summer. They suck the juices of the foliage and twigs, 

 and some produce gall-like swellings on the new-grown twigs 

 of conifers, poplars, etc.; noteworthy only if unusually 

 developed. 



Spray at any time during the season with dilute kerosene 

 emulsion (one part in tif teen parts of water) , or with tobacco 

 decoction, or with common soap solution (one pound in 

 eight gallons). 



Bark-lice and Scales, mostly dull }-ellow-brown to black, 

 hemispherical, globular, or convex bodies, the "scales" 

 formed by excretions, the males winged, the wingless females 

 attached to the smooth-barked twigs or leaves, from which 

 they suck the sap, and where they winter, resuming their 

 feeding and the laying of eggs in spring. 



Besides various fruit trees, dogwoods, mountain-ash, 



