CHAPTER XVI 



FOES AND FRIENDS OF THE PLANT (Continued) 

 SUCKING INSECTS (BUGS) 



THE name " bug " is property given only to insects 

 which have jjgaks with which to suck up their food. 

 Plant lice and scale insects are bugs. Mosquitoes and 

 flies are not bugs, because their sucking organs are 

 very different from the simple beak of the bugs. 



Sucking insects may be kept in check by sprays 

 which kill them by touching them. Sprays such as 

 arsenate of lead or Paris green, which kill only when 

 eaten by the insect, have no effect on the sucking in- 

 sects, because the arsenate of lead stays on the outside 

 of the leaf, while the bug takes its food from the inside 

 by sucking up the juices (see page 183).. 



PLANT LICE OR APHIDS 



These are the very small green bugs so common on 

 all sorts of plants, in doors and out. The tips of rose 

 branches and the leaves of cabbage and mustard are 

 often covered with them. They suck the juices from 

 the young and tender parts of the plant and may do it 

 great harm. 



If you find many plant lice on a plant, you are almost 



210 



