INJURIOUS TO CABBAGE AND RELATED CROPS 31 



a cabbage plant is seriously infested is a tendency to wilt badly 

 in the heat of the day ; the leaves take on a bluish cast and then 

 in a few days the plant 

 droops and dies or it may 

 survive in a sickly condi- 

 tion for some time. When 

 the maggots are present 

 in great numbers, the root 

 is riddled with their bur- 

 rows, decay sets in and 

 the death of the plant 

 quickly ensues. In such 

 cases great numbers of the 

 maggots may be found in 

 the soil surrounding the 

 root, moistened by the 

 juices of the injured plant 



Fig. 27. — Cabbage root-maggots 

 the base of an injured plant. 



at 



(Fig. 27). The maggots become 



full-grown in about three weeks. 



They are then nearly J inch 

 in length and shin- 

 ing white in color. 

 The body tapers 

 toward the head, 

 r^ being largest be- 

 ^^ hind, where it is 

 obliquely truncate. 

 The mouth-parts 

 consist of a pair of 

 strong black hooks 

 curved downward, 

 by which the insect 

 is able to rasp off 

 portions of the 

 plant tissue. The truncate surface at the posterior end of the 

 body is surrounded by a row of twelve fleshy tubercles, of 



Fig. 28. — The cabbage root-maggot, side view 

 ( X 8) ; a, dorsal view of caudal seginent, showing 

 size, number and arrangement of fleshy tubercles, 

 much enlarged ; b, outline of a cephalic spiracle, 

 greatly enlarged. 



