ORCHARD, GARDEN, AND FIELD INSECTS 121 



a 



FIG. no. A BUG 



side view of sucking, mouth part 



It is important to know how insects take their food, for 

 by knowing this we are able oftentimes to destroy insect 

 pests. Some are pro- 

 vided with mouth parts 

 fitted to bite their food ; 

 others have a long tube 

 with which they pierce 

 plants or animals, and, 

 like the mosquito, suck 

 their food from the in- 

 side. The insects of this 

 latter class cannot of 

 course be harmed by 

 poison on the surface 

 of the leaves on which 

 they feed. 



Many insects change 

 their form from youth to 

 old age so much that you 

 can scarcely recognize 

 them as the same beings. 

 First comes the egg. 

 The egg hatches into a 

 wormlike animal known 

 as grub, or caterpillar, or 

 more accurately larva. 

 This creature settles 

 down and spins a home 

 of silk, called a cocoon (Fig. 115).' If we open the cocoon, 

 we shall find that the animal is now covered with a hard 

 outside skeleton, and that it cannot move freely, and that 



FIG. in. BEETLE 

 Larva, pupa, adult, and burrow 



