54 ADDENDA. 



The larvae reach their full growth in about two weeks. 

 The smaller end, which is the head, is armed with a pair of 

 black, hook-like jaws. The opposite end is cut off obliquely ; 

 and there is a pair of small, brown tubercules near the 

 middle, and eight tooth-like projections around the edge. 



The larva usually leaves the onion, and transforms to pupae 

 in the ground outside. They remain in the pupa state about 

 two weeks in the summer, when the perfect flies emerge ; 

 after pairing, the female deposits her eggs for another gener- 

 ation. The winter is passed in the pupa state ; and the flies 

 emerge in the early part of June, or about the time that the 

 young onions are sufficiently grown to furnish food for the 

 young maggots. 



The fpllowing preventives and remedies have been 

 suggested : — 



Instead of sowing onion seed in rows, where the young 

 seedlings grow in contact, or nearly so, giving every facility 

 for passing from one to another, they should be grown in 

 hills, so that the larvae cannot make their way from one hill 

 to the other. 



Scattering dry, unleached wood-ashes over the beds as 

 soon as the plants are up, while they are wet with dew, and 

 continuing this as often as once a week through the month 

 of June, is said to prevent the deposit of eggs on the plants. 



Planting the onions in a new place, as remote as possible 

 from where they were grown the previous year, has been found 

 useful, as the flies are not supposed to migrate very far. 



Pulverized gas-lime scattered along between the rows has 

 been found useful in keeping the flies away. 



Watering with the liquid from pig-pens, collected in a 

 tank provided for the purpose, was found by Miss Ormerod 

 to be a better preventive than the gas-lime. 



