340 



The Apple- Worm and the Apple- Maggot. 



while that of the second is what is technically termed a "coarctate " pupa, — 

 that is to say, instead of the larva moulting its skin to assume the pupa 

 state, the larval skin is retained vvhole and unbroken, although greatly con- 

 tracted in length by the pupa, so that the true pupa can only be seen by 



dissecting away the shrunken skin of the larva. The little elongate-oval, 

 mahogany-brown bodies that we often see in cheeses infested by the com- 

 mon cheese-fly {Piophila casci), afford a familiar example of this peculiar 

 kind of pupa ; and any one may easily satisfy himself that they are really 

 the pupae of the cheese- fly by enclosing a few of them for a few days in a 

 vial till the perfect fly comes out from them. 



But not only is the apple-worm structurally distinct from the apple-mag- 

 got, but the habits of the two insects differ very remarkably. The former 

 comes out from the pupa in the perfect or winged state quite early in the 

 summer, or about as soon as the young apples are the size of hazel-nuts : 

 the latter does not come out till the middle and latter end of July. Hence 

 apple-worms are commonly met with in June, but apple-maggots never till 

 August and September. Again : in one and the same year, there are two 

 successive broods of the apple-worm moth ; the first coming out in June 

 from pupae which have lived in that state through the winter, and the second 

 coming out about the latter part of July from larvae generated in June by 

 the first brood. On the contrary, in one and the same year, there is but 

 one brood of apple-maggots, which is generated by the flies that come out 

 in July, and never transforms into the fly-state the same season. Further- 

 more, the apple-worm spins a slight silken cocoon above ground ; while the 

 apple-maggot spins no cocoon at all, and burrows under ground to pass into 



