PLANT PESTS 141 



(a) Consumers of entire leaves. 



(b) Leaf skeletonizers, that eat out the soft parts, leaving 

 the large veins. 



(c) Sap feeders, bugs and thrips, whose puncturing 

 mouthparts penetrate to the sap and suck it out, 

 leaving the leaf shrivelled and empty. 



(d) Leaf miners, that eat out a residence chamber in the 

 inner leaf tissues, leaving the skin (epidermis) intact. 



(e) Gall insects, that feed within excrescences whose 

 growth upon the leaf they stimulate. 



The two last mentioned live within the leaves; and some 

 of the others make for themselves shelters by fastening leaves 

 together that cause them to be known as leaf-rollers, leaf- 

 crumplers, leaf-folders, and leaf-tyers;or they make portable 

 shelters of such sort that they are called casebearers and 

 bagworms. 



All these habits intergrade; and leaf-eating in general 

 intergrades with feeding on green stuffs elsewhere, in stems 

 and buds and young fruits. 



2. Destroyers of roots and tubers. — These work beneath 

 ground, some of them boring also into the stems. They con- 

 sume both growing and stored root crops, but only a few 

 go with the root crops into storage. Most important among 

 them are the root maggots, the wire-worms, the root borers, 

 the root worms and the tuber worms. 



3. Destroyers of fruits and nuts.- — These, like ourselves, 

 take advantage of the food stores that plants accumulate. 



