112 



BULl.ETIN 142. 



just as they appeared 011 the piece of bark when it was removed from 

 the tree. Figure 136 shows some cocoons enlarged, and it well illus- 

 trates their method of construction. In shape, the cocoons are adapted 

 to the shape of the place in which they are built. Anyone can soon 

 find these cocoons on old rough-barked apple-trees after a little search 

 at almost any time from August i until spring opens. Cooke states 

 that a worm completes its cocoon in twenty-four hours. It is said that 



the cocoons made by the worms 

 late in the season, and in which 

 they expect to pass the winter, 

 are tougher, thicker and darker 

 colored than those made earlier, 

 from which the moths soon 

 issue. 



Hoiu Long and in Uhat Con- 

 dition the Ijisect Lives in Its 

 Cocoon. 



Usually when the cocoon is 

 made during or after August, 

 the insect may be found therein 

 as a caterpillar until the next 

 spring. If the cocoon is made 

 before August i, its maker, the 

 caterpillar, may change within 

 three days to a very ditTerent 

 looking object known as the 

 t^upa. Cocoons containing these 

 pupce are shown, natural size, in 

 figure 135, and enlarged in 

 figure 136. The insect usually spends but two or three weeks, 

 sometimes less, in the pupa state, whether the change to a pupa 

 takes place in July or not until the next spring. 'J'luis the insect 

 may spend less than three weeks of its life as a pupa in the 

 cocoon, or it may occupy il as a caterpillar for ten months, and then 

 as a pupa for two or three weeks longer. The reason for this seem 

 ingly great variation in the life-history of the codling-moth will appear 

 in the discussion of the next and very important phase of the subject. 



135. — Cocoons of the codling-moth as they 

 iue)e found attached to a piece of loose 

 bill k, natural size. 



