150 Control of Parasites 
1. Bucs, comprising a number of insect families sep- 
arated in strict classification into Hemzpiera (half-wings, 
partly leathery), Ovthopiera (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 fifteen parts of water), or with tobacco 
decoction, or with common soap solution (one pound in 
eight gallons). 
Bark-lice and Scales, mostly dull yellow-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, 
