^^ 



19 



^ao 



Fig. 11. 



They usually leave the onions and transform to pupae within the 

 ground. The form of the pupa does not differ very much from the 

 maggot, Dut the skin has hardened and changed to a chestnut-brown 

 color, and they remain in this stage about two weeks in the summer, 

 when the perfect flies emerge. There are successive broods during 

 the season, and the winter is passed in the pupa stage. 



The following remedies have been suggested : 



Scattering dry unleached wood ashes over the plants as soon as 

 they 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 

 useful in keeping the flies away. 



Watering with liquid from pig pens collected in a tank provided 

 for the purpose, was found by Miss Ormerod to be a better preven- 

 tive than the gas lime. 



When the onions have been attacked and show it by wilting and 

 changing color, they should either be taken up with a trowel and 

 burned, or else a little diluted carbolic acid, or kerosene oil, should 

 be dropped on the infested plants to run down them and destroy the 

 maggots in the roots and in the soil around them. 



Instead of sowing onion seed in rows, they should be grown in hills 

 so that the maggots, which are footless, cannot make their way from 

 oue hill to another. 



THE CABBAGE BUTTERFLY. 



Pieris rapae (Linn.) 



In the New England States there are three broods of this insect in 

 a year, according to Mr. Scudder, the butterflies being on the wing 

 in May, July and September ; but as the time of the emergence varies, 

 we see them on the wing continuously through the season. 



