39 



In July^ 1867, from larvae and pupse received from Connecticut, 

 Massachusetts and New York in the preceding winter, I bred several 

 specimens of the perfect fly, a magnified figure of which is given here- 

 with. (Fig. 2.) It will be seen at once that it has no resemblance 

 whatever to the Codling Moth or moth of the Apple-worm, which is 

 a four-winged insect with easily removed scales on its wings, like all 

 other moths or "'millers,"' and belongs to the Order Lepidoptera; 

 whereas the perfect insect of the Apple-maggot is a two-winged fly, 

 with no scales whatever on its wings, and belongs to the same Order 

 (Diptera) as mosquitoes, gnats, midges, horse-flies, house-flies, etc., 

 and to the same great group as our common house-fly. The larvae also 

 of the two insects are notably unlike. The Apple-worm (fig. 2b) is a 

 cylindrical, 16-legged caterpillar with a large, dark, horny head and a 

 dark horny patch behind its head; the Apple-maggot (fig. 2a) is a 

 legless maggot, tapered to a point in front and not very unlike the 

 larv« of the different blow-flies that lay their eggs, or "fly-blows" as 

 they are cojnmonly called, on meat. Even the pupse are quite dis- 

 similar. For that of the Apple-worm shows the wings of the future 

 moth, soldered indeed to the side of the body, but still plainly visible, 

 while that of the Apple-maggot is what is technically termed a "coarc- 

 tate" pupa; that is to say, instead of the larva moulting its skin to 

 assume the pupa state, the larval skin is retained whole and unbroken, 

 although greatly contracted 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 cheese infested by the common Cheese-fly (Piophila casei, Lin- 

 nasus) afford a familiar example of this 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 per- 

 fect fly comes out from them. Again, the Apple-worm, as we have 

 already seen, is double-brooded, the first brood of Moths appearing in 

 June and laying its eggs in the blossom end of the apples when they 

 are no bigger than hazel-nuts, and the second brood of Moths appear- 

 ing about the beginning of August to work on the more fully matured 

 fruits. The Apple-maggot, on the other hand, is single-brooded, the 

 perfect flies not making their appearance till July, and the maggots, 

 produced from the eggs inserted by the ovipositors of these flies into 

 the flesh of the apple, not changing back again into flies till the fol- 

 lowing July. Furthermore, 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 the pupa state, remaining un- 

 der the surface of the earth, without eating anything, all through the 



