feed upon the juicee and tissues inside the plant. II. Those 

 that suck the juices of plants, in which case one finds no 

 parts of the plants eaten away, but the leaves shrivel up and 

 dry or turn another color. These are called sucking insects. 

 They pierce the plant with their mouth-parts and simply 

 suck the juices. III. Those that eat the parts of plants, in 

 which case we find places eaten away, or parts eaten or cut 

 off, as we say. These are called biting insects. They feed 

 upon at least the outer parts of plants and in most cases the 

 inner tissues at the same time. 



Remedies. — From the nature of the case, it is evident that 

 each of the three groups of insects as above described will 

 require a different mode of treatment. 



In general (special and exceptional cases will be noted 

 under their respective heads) the best if not the only way 

 to get rid of the borers is either to dig them out or, as has 

 lately been successfully done in the case of the peach tree 

 borer, pour hot water on that part of the tree that is infected. 

 The application of chemicals after the insect is once inside 

 the plant is of little or no use, since the plant would be 

 killed before the insect could be reached. The application 

 of chemicals to prevent their entering has succeeded in some 

 cases. Paris green or London purple mixed with water (see 

 formula under insecticides) and thrown in the form of h spray 

 (apparatus for spraying will be explained later) on to the 

 plant or parts of the plant liable to be infected, has resulted 

 in lesseningf the attack in a number of cases where the in- 

 sect or its young eat their way in through the outer tissue, 

 but where the adult deposits its eggs inside the tissue be- 

 neath the outer layer, this method is of little value.- The 

 application of certain substances like coal tar, tobacco, etc., 

 is sometimes used as a repellant. Methods and contrivances 

 to keep the insect away will be noted under the special in- 

 sect. 



The sucking insects cannot be destroyed by putting poison 

 like Paris green on the plant, since these insects do not eat 



