496 Bulletin 78. 



stripes and a sub-continuous stripe of rather indistinct narrow triangular 

 black spots down the dorsum of the abdomen. A glance at the hind femur 

 of the male Onion Fly will readily distinguish it from the one infesting cab- 

 bage. At a in figure 6 is shown the right hind leg of the male Onion Fly 

 greatly enlarged, and at b, the same leg of the Cabbage Fly ; the tuft of 

 hairs at the base of the femur in <^ is a striking contrast to the comparatively 

 bare base of the femur of a, the Onion Fly. The female flies of these two 

 species are not easily separable unless found associated with their males. 



As the name of this onion pest indicates, it is closely allied to 

 the Cabbage Root Maggot ; they belong to the same genus, 

 Phorbia. Its specific name ceparum comes from the specific name 

 of its food-plant, the onion (^Allium cepa). 



The life-history of the Onion Maggot, so far as recorded, shows 

 that it is very similar to that of the Cabbage Root Maggot. 

 Thus our discussion of this phase of the latter insect will be of 

 equal interest, in many respects, to onion growers. From the 

 nature of the difference in the vegetables attacked, the Onion 

 Maggot probably differs somewhat in its habits, but many of the 

 statements we make regarding the life-history of the Cabbage 

 Root Maggot will also apply to the Onion Maggot. 



Some, and doubtless all, of the natural enemies which we 

 record as attacking the Cabbage Root Maggot, also prey upon 

 the Onion Maggot. 



Our detailed discussion of the methods of preventing the rav- 

 ages of the Cabbage Root Maggot, especially when it attacks 

 radishes, will be found equally applicable to this most formidable 

 pest of the onion grower. 



Therefore, onion growers should tmderstand that although this 

 bulletin primarily treats of the Cabbage Root Maggot, much that 

 it contains applies equally well to their worst pest, the Onion 

 Maggot ; especially is this true as regards the discussion of the 

 life-history and methods of combating the former pest. 



THE ROOT MAGGOT. 



Anthoniyia radicum, L,inn. 



Although this insect has been known for more than a century 

 (it was described by Linnaeus in 1761), our knowledge of its 



