76 INSECTS AND MAN 



summation the insect spins a silken web as it wanders over 

 the fruit, and, using this as a foothold, it is able to make 

 some impression on the skin. When once the skin is 

 broken, progress is more rapid ; chip after chip of apple is 

 bitten out and dropped into the web, till the larva is partly 

 hidden, then it backs out of its burrow, bringing pieces of 

 apple out with it. This process is repeated till the insect 

 is quite hidden, when, turning round, it spins a silken door 

 over the hole. Unless the larva has partaken of a leaf diet, 

 its first meal is eaten when hidden within the burrow, for 

 none of the fruit is eaten during the tunnelling operations. 

 By the time it is a week old, the larva has reached the 

 core. As it travels towards this point, it pushes its ex- 

 crement and frass through the entrance hole, and the 

 brown powdery mass which gradually collects there is 

 characteristic of infested fruit. When nearly full-grown, 

 the caterpillar tunnels its way out of the apple, travelling 

 as a rule away from the entrance hole, then, leaving the 

 fruit, it usually crawls along the branches to the stem, where 

 it spins its cocoon beneath some rough bark, or in a con- 

 venient crack, if one be at hand, or, should the tree have a 

 smooth bark, it passes to the ground and pupates beneath 

 some hiding place at its foot. Occasionally, though this 

 is not the normal procedure, the larvae will lower them- 

 selves to the ground by means of a silken thread; this 

 probably only occurs when the larvae slip from the fruit by 

 accident, in which event the thread is spun to save them- 

 selves in falling. Should the apple be on the ground before 

 the caterpillar is ready to pupate, it will, on leaving the 

 fruit, simply crawl into the nearest hiding place to spin 

 its cocoon. Whatever the method selected by the insect, 

 one thing is certain, and that is, that after abandoning the 

 fruit it wastes no time in spinning its cocoon. If the larva 

 is one of the first brood, it changes into a pupa in about 

 six days, and about three weeks later the adult moths 

 emerge. If, on the other hand, it is a second-brood larva, 



