INSECTS 



233 



by the malarial mosquito. Even the common mos- 

 quito is an intolerable pest, although not a carrier of 

 disease. The house fly, now called the typhoid fly, 



is often the agent that car- 

 ries typhoid germs from in- 

 fected matter to our food. 



Classes of insect pests. - 

 Insect pests are of five gen- 

 eral classes : (i) those which 

 eat the leaves and stems of 



SPRAYING TREES AND VEGETABLES 



plants ; (2) those which suck the juices of plants ; 



(3) those which bore into plants, feeding on the inside 

 of tree trunks, stems of smaller plants, fruits, and seeds ; 



(4) those which suck the blood of animals ; (5) those 

 which are carriers of infected matter. 



