50 



FLIES. 



and from it, in due time, cracks its way out ; but 

 meanwhile the coming Fly is wonderfully safe in all 

 circumstances. It is in a little chamber, which pro- 

 tects it from drought and wet and evil influences ; and 

 consequently the common crop Flies are not as easily 

 to be got rid of in the pupa or chrysalis state as many 

 other attackers. 



However much our crop Flies may differ in the part 

 of the plant the maggot feeds on, there are many 

 which are so much alike, in the maggot turning to 

 the above kind of pupa, in the ground,- that there are 



]FiG. a. — Turnip leaf-miner, Fly maggot and pupa ; nat. size and 

 masnitieJ. Blistered leaf. 



some means of prevention which apply equally well 

 to many kinds of attack. 



The Onion maggots feed in the putrefying bulbs, 

 and then usually leave them, and turn to brown oval 

 pupa) in the ground near the destroyed bulb, though 

 sometimes they are stored in it during the winter. 



The Cabbage-root maggots also turn to brown oval 

 pupse in the ground, and so does the maggot of the 

 Carrot Fly. This maggot, when feeding, may be seen 

 with its tail sticking out of the rusty-coloured injured 

 parts, which give this attack the name of rust ; and 

 in due time we find the brown pupa-cases close by. 

 (See Fig. 22, p. 27.) 



