CABBAGE. 155 



LIGHT-COLORED CABBAGE-WOKMS. 



The following three, viz., the Rape Butterfly (Pieris 

 rapce), the Pot-herb Butterfly (P. oleracea), and the 

 Southern Cabbage-Butterfly (P. Protodice), are white or 

 cream- colored butterflies. The first two are more nu- 

 merous and destructive than the third, our native South- 

 ern species. The larvae and butterflies bear a general 

 resemblance to each other, though they differ in their 

 markings, as will be seen by an examination of the 

 engravings. 



All of these cabbage- worms have their insect enemies. 

 The Pot-herb Butterfly has lately been kept in check by 



Fig. 27. POT-HERB BUTTERFLY (Pieris olercecn). 

 a, Larva; ft, Butterfly ; c, Chrysalis. 



its own appropriate parasite (Pteromalus puparwn), a 

 little greenish wasp-like insect, less than one-tenth of an 

 inch in length, with four delicate transparent wings. 

 These butterflies almost invariably deposit their eggs on 

 the under surface of the leaves. They hibernate gen- 

 erally in the chrysalis state, attaching themselves to 

 fences, stems of bushes, etc. , in the vicinity. 



If boards were fixed in the cabbage field, about two 

 inches above the ground, these worms would probably 

 resort to them, but such methods to capture them and 

 diminish their number, after the infliction of the dam- 



