MISCELLANEOUS GARDEN INSECTS 423 



The outer skin of the maggot now becomes hardened and 

 within it the insect transforms to the pupa, which remains in the 

 soil at the base of the plant for about two weeks, when the adult 

 fly emerges. Two or three gensrations probably occur in the 

 Northern States. Professor R. H. Pettit states that some of the 

 flies hibernate while many of the pupae remain in the soil over 

 winter and the flies issue from them in the spring. This com- 

 plicates remedial measures. 



Control. Liberal applications of commercial fertilizers such as 

 nitrate of soda, which will assist to rapid growth, are of great value 

 in overcoming injury by all root-feeding pests. Thorough culture 

 is of value. Rotation of the onion plot to a point far distant 

 from that of the previous year, the cleaning up of old beds, and 

 plowing them deeply in the fall, will aid in the control. Pull up 

 and destroy the young plants affected as soon as noticed, being 

 careful to dig up the maggots with the roots. The application of 

 carbolic emulsion as for the cabbage-root maggot has been advo- 

 cated and will doubtless lessen the injury by repelling the adult 

 flies. Concerning it see page 354. Apply early in the season and 

 at intervals of a week. 



The Barred-winged Onion-maggot * 



The adult flies of this species may frequently be found upon 

 corn and are readily recognized by the banded wings. They are 

 similar in size to the last species, but the back is metallic blue-green 

 except the head , which is mostly hoary, with brownish-black eyes. 

 The maggots have been recorded as injurious to corn and sugar- 

 cane and have been recently noted in Michigan associated with 

 the common onion-maggot, destroying onions. f The maggots 

 are similar to the onion-maggot but the posterior end is more 

 rounded and may be distinguished from the illustrations. The 

 winter is passed in the puparium as far as observed. 



Remedies. In addition to the measures advocated for the last 



* Choetopsis oenea Wied. Family Anthomyidae. 



t See Pettit, Bulletin 200, Mich. Agr. Exp. Sta., p. 206. 



