116 LIFE ON THE FARM. 



pores, are called spiracles. The spiracles are so 

 small that dust stops them up and breathing can- 

 not take place. Thus the insects die in the dust 

 bath. When infested with lice, birds will take a 

 dust bath in any kind of dry earth. Domestic 

 birds prefer ashes when they are to be had, and 

 will wallow in them in preference to dry earth. 

 Ashes act as dust to stop up the breathing pores of 

 insects, and the alkaline properties attack the tissue, 

 making the destruction doubly sure. Man has 

 copied from nature here and uses several kinds of 

 dust to kill insects with. Ordinary road dust is 

 often used. Lime and ashes are both good, and 

 besides are excellent food for the plants when 

 washed into the soil. 



Poisons, such as Paris green, London purple, 

 and sulphate of copper are often sprayed upon 

 plants infested with insects. The insects eat the 

 leaves, take the chemicals into the system, and die 

 by poisoning. 



Kerosene, carbolic acid, and similar substances 

 are used because of their strong power to attack 

 and destroy animal tissue. They literally blister 

 or burn insects to death. A mixture of kerosene 

 and soap, or soap alone, may be used with similar 

 results. Soap is very good for the soil, too. 

 There are three general principles then, in killing 

 insects stopping up the breathing pores, poison- 

 ing, and burning or blistering the tissues. 



Large worms, or caterpillars, are sometimes 



