The Anthomyia Flies 



in the larval stage is occasionally very destructive to onions, 

 working into the bulb and destroying it for food. The cabbage 

 maggot (P. brassica:) works in the roots of cabbage and some- 

 times does great damage. Some species in the larval stage mine 

 the leaves of plants. Pegomyia vicina mines the leaves of beets 

 and has become a rather important insect since the cultivation of 



Fig. 98. — Pegomyia vicina. (Author's illustration.) 



the sugar beet has assumed large proportions in this country. 

 One species is said to damage seed corn when placed in the 

 ground and others destroy injurious grasshoppers and there are 

 records which show that other forms sometimes live in tumors 

 under the skin of birds. 



172 



