EXPERIMENT STATION REPOET. 



551 



there may be only a spring or spring and fall brood, but in every; 

 case the larval life is short, and the life of the adult extends 

 through an unknown period. 



The Materials to be Tested. 



Some of the applications to be made were of well-known ma- 

 terials, with which contradictory results had been obtained, and 

 *ome were tried simply to see how results in different hands and in 

 divei-'^e localities? would compare. 



^^^^S§g|^^S5g 





Fig. 13. 



Hind leg of male Onion Fly (1) and of male Cabbage Fly (2) ; much enlarged. Original. 



1. Ground Tobacco: to he dusted liberally around the plants on 

 the surface of the gi-ound. Is intended as a repellant, must be in 

 place before the eggs are laid and must be renewed at short inter- 

 vals until all flies have disappeared. It was also desired to- learn 

 whether the leaching from the ground tobacco would kill the young 

 larvse provided any hatched before the tobacco was in place. 



