CELERY AND PARSNIP FLY. 49 



blunt at the tail, white or pale greenish in colour. They feed 

 between the upper and under sides of the Celery-leaf, and, by 

 eating away the substance, cause large blister-like patches, 

 which are white at first, and turn brown as the skin dries. 

 Where there are many of these blisters, the leaves are des- 

 troyed, and the plants are consequently destroyed or much 

 injured. 



When the maggots are full-fed, the skin hardens, and they 

 turn to brown or ochry oval pupae (or chrysalis cases) in the 

 leaf or in the earth ; generally they leave the leaf and turn to 

 pupffi in the earth. 



The "miner" maggots go through their changes from the 

 egg to the perfect fly so rapidly as to give time for two or 

 more broods during the year. The fly is rather more than 

 the eighth of an inch long, and about three-eighths of an inch 

 across in the spread of the wings. 



The colour is ochreous or brown, the eyes deep green, and 

 the two wings are transparent and mottled with patches of 

 brown. The poisers (that is, processes like a knob on a short 

 stalk, which project from the body and take the place of the 

 second pair of wings in the Diptera, or two- winged flies) are 

 ochre -coloured. 



They may be found in great numbers in the middle of May, 

 and grub-blistered leaves may be found from the time the 

 Celery is planted out till Christmas. 



The maggots of the autumn brood turn to pupae, and remain 

 in the ground in that state during the winter. 



Prevention and Remedies. — Something might be done in 

 the way of prevention by attending to the ground on which 

 infested crops have been grown (and which is almost certainly 

 full of the pupa3) : — The greater part of the maggots go down 

 into the earth to change to pupte, that is, to the little brown 

 cases, out of which the fly will come up presently; these 

 pupae may be found in multitudes if the soil is turned up. 

 Where there has been a bad attack, it would be a good plan 

 to skim off the soil to a depth of about three or four inches, and 

 burn it (if only a small quantity), or get rid of it thoroughly, 

 with its contents, in any other way that may be preferred. 



If this process cannot be carried out, the ground might be 

 trenched, care being taken to turn the top spit into the bottom 

 of the preceding trench, and so bury the pupae too deep for 

 them to develop and come up again as flies. Eough-digging 

 might be of benefit, by placing some of the fly-cases within 

 the reach of birds, and burying others in the same manner as 

 in trenching. A more certain plan, however, would be to give 

 the ground a dressing of fresh gas-lime, which, on being 



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