INJURIOUS INSECTS 



127 



and both of them are very destructive to cabbage, turnip, 

 cauliflower, and similar vegetables, and to such flowering 

 plants as mignonette, stocks, and nasturtiums. They feed 

 on the leaves and will often destroy the cabbage crop unless 

 preventive measures are taken. The worms of the imported 

 species are green in color, while our native species are bluish 

 with yellow stripes. The butterflies of both species are 

 much alike. They are generally white with indefinite 

 black marks above and yellow or green markings on the 

 under side, and are commonly seen flitting over fields of 



Fig. 44. The cabbage worm; a, larva; b, chrysalis; c, adult male; d, adult female. 



cabbage or of other of its food plants during the day time. 

 The full-grown caterpillar is about an inch and a half long. 

 The winter is passed in the chrysalis stage hidden away in 

 sheltered places, and from these the adult butterfly emerges 

 in the spring and lays her eggs on the under side of the 

 leaves, where they hatch in about one week. There are 

 several broods in a season. 



Remedies. Pyrethrum powder mixed with five times 

 its bulk of flour and dusted into the cabbage just at night- 



