INSECTS — INJURIOUS AND BENEFICIAL 197 



works inside it, but which does not become noticeable until 

 the summer months; still another is the yellow-necked cater- 

 pillar, which feeds on the apple foliage. There are other 

 species, much like the yellow-neck, which feed in great num- 

 bers on walnut, hickory, and other trees. Finally, there is the 

 green cabbage-worm. The adult from all caterpillars is 

 either a moth or a butterfly. 



The eggs of the tent-caterpillar and of the fall web-worm 

 are laid in masses on the trees. The larvae feed greedily on 

 the leaves and when full grown they drop to the ground and 

 change to the chrysalis form. The tent-caterpillar changes 

 to the adult stage before cold weather and lays its eggs for 

 next year in a compact mass completely encircling a twig. 

 The second brood of the fall web-worm does not change to 

 the adult form until spring. 



The yellow-necked caterpillar and its close relatives hatch 

 from eggs laid on the leaves. The young feed together 

 until they are nearly grown, when they begin to scatter over 

 the tree. They change to the pupa stage in the ground and 

 remain there until spring. One can see the moulting habit 

 in this insect better than in almost any other. When they are 

 ready to change their skins they travel down to the trunk of 

 the tree and gather in a large mass. In about a day they slip 

 out of the old skin and travel back to their feeding-place. 

 However, they take a new place each time. They shed 

 their skins three or four times, each time leaving the mass of 

 empty skins hanging on the body of the tree. 



The beautiful white butterfly which lays the eggs for the cab- 

 bage-worm is known by every one. The eggs are laid singly 

 on the under side of the cabbage leaf. When the larvae are 

 ready to pupate they enclose themselves in a papery cocoon. 



