144 ELEMENTARY STUDIES IN INSECT LIFE 



senites. They can, however, be reached by what we speak 

 of as contact poisons, the best of which is kerosene emul- 

 sion. (For directions for making, see page 305.) This 

 spray is a contact poison, since it kills the insect by com- 

 ing in contact with its body, and not by entering the ali- 

 mentary canal as is the case with arsenical poisons. 

 Since these insects spend the winter in the adult stage in 

 rubbish left about the garden plots or fields where vines 

 of this family are cultivated, all such refuse allowed to 

 remain favors their hibernation. In the fall, then, all 

 vines and rubbish about garden plots should be raked up 

 and burned, and in so doing many of the insects will 

 doubtless be destroyed at the same time. 



The Cabbage-Worm. 1 - -Farmers who are engaged in 

 the production of cabbage for market, as well as those 



Fia. 115. Cabbage butterfly (Picris rapce), parent of the 

 cabbage-worm. Drawn from nature, by Miss M. E. Wise. 



who raise only for home consumption, find considerable 

 difficulty with the small greenish worm known as the 

 cabbage-worm. The parents of this cabbage-worm 

 were brought from Europe. They are about one and 

 one-half inches in wing expanse, white or creamy white 

 in color. The male has a single black spot in the fore 



rapce. 



