214 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 4 



TABLE III 



COMPARATIVE MEASUREMENTS OF THE CEPHALO-PHARYNGEAL STRUCTURES 

 AND OF THE SIZE OF THE LARV^ 



Aerial Habits of the Larva 



The question of removing the stumps from the field after the cabbage 

 crop has been harvested has frequently been discussed by entomol- 

 ogists. The advisability of such a procedure depends upon the num- 

 bers of injurious insects that would be killed or avoided. To obtain 

 data on this point a number of fields were inspected in this locality 

 and on Long Island. 



The stumps examined, and especially those from which "early" 

 cabbage had been cut, were found to contain maggots. Some of these 

 were feeding upon the root, but the majority of them were found in 

 the upper part of the stalk, at the base of the leaves and in the cortex 

 of the adventitious buds. The maggot has generally been considered 

 a subterranean insect, and little mention seems to have been made to 

 an aerial habit. The fact that in some fields a large percentage of the 

 larvae work in the top part of the plant during September and October 

 is thought important because of the possibilities of reducing the 

 numbers of these insects by the timely removal of these crop remnants. 

 Adults and eggs have been observed in considerable numbers about 



