18 



are gregarious aiul when not feeding, rest together in great numbers 

 on the branches. When mature (Fig. 9) they are fully an inch and 

 a quarter in length and quite stout. The body is longitudinally 

 striped with black alternating with yellow or whitish lines. The 

 head is bright red. Blunt, black, hair-tipped spines arranged in a 

 double row occur on the back, the longest being borne on the summit 

 of a prominent, reddish hump arising from the fourth segment; 

 similar but shorter spines occur on the sides. The hindmost pair of 

 legs is not used in walking, and when at rest the last three segments 

 of the body are always elevated. 



AVhen young the caterpillars feed only on the under surface of the 

 leaf, but later they devour the entire leaf. At maturity they descend 

 to the ground, and, concealing themselves in rubbish, they spin 

 silken cocoons within which they remain, still in the caterpillar state, 

 until the following May when they change to pupoe from which the 

 moths emerge about the first of July. There is but a single brood 

 in a season, but it frequently happens that some of the moths are 

 late in emerging and so caterpillars in ditlerent stages of growth may 

 be found throughout the summer. 



Fig, 10.— Kbd Humped Apple Tkee Caterpillar Moth. (After Saunders.) 



The moth (Fig. 10) is not a very showy creature and is seldom 

 noticed. It measures about one and one-quarter inches across its 

 expanded wings. The fore wings vary from dark brown near the 

 hinder margin to grayish along the front, and bear several dark spots, 

 the most conspicuous being near the middle. The hind wings are of 

 a lighter shade of brown, often becoming dirty white in the male. 

 The thorax is deep gray with darker shoulder covers and a dark 

 brown patch at the hind border. The abdomen is light brown. 



This insect is most troublesome on apple trees, but occurs very 

 fi'equently on all orchard trees as well as on blackberry and rose 

 bushes and many other shrubs and trees. 



As the caterpillars feed in colonies the problem of destroying them 

 is comparatively simple. The branch they are on may be cut ott" and 



