62 



ELEMENTAEY AGEICULTURE 



Insects with biting months have two pairs of jaws 

 with which they chew their food ; and they often eat 

 bark, leaves, fruit, and flowers. All these biting 

 insects may be killed by spraying poison on the 

 plants on which they feed. 



Sucking Insects. Insects with sucking mouths 

 usually live upon the sap of plants or the blood of 







Courtesy U. S. Dept. of Agriculture 



Fig. 38. Knotty apples from trees that were not sprayed. 



animals. Some few of them, such as bees and but- 

 terflies, feed largely upon the nectar or sweets of 

 flowers. Since they get their food from the inside 

 of the objects on which they feed, we can not poison 

 them, but must find some other method of fighting 

 them. 



Contact Insecticides. Substances have been dis- 

 covered which will kill insects when covering or 

 touching their bodies. These are called contact 



