INJURIOUS TO CABBAGE AND CRUCIFEROUS CROPS 349 



long, white or yellowish in color, tapering toward the head and 

 obliquely truncate at the tip of the abdomen. From the head a 

 pair of strong, black, hook-like, rasping jaws project downward, 

 and just back of the head on either side is a minute, light brown, 

 fan-like projection (Fig. 253, 6), or spiracle, which leads into the 

 breathing system. The oblique posterior end is surrounded by 



FIG. 250. The cabbage maggot fly (Pegomyia brassicce Bouch6), female 

 greatly enlarged. (After Slingerland.) 



twelve rounded tubercles and in the centre are two brownish spira- 

 cles (Fig. 253, a). When done feeding the larva burrows one-half 

 to one inch under the surface of the soil, and the outer skin gradually 

 hardens until it forms a firm brown shell, called a puparium, 

 within which the larva transforms to a true pupa. Frequently the 

 puparia are found in the galleries made by the maggot or in crevices 

 of the roots. During the summer this stage lasts about two weeks, 

 but in the fall most of the insects remain in this condition over win- 



