The Cabbage Root Maggot. 487 



This experiment suggested an examination of plants in the field. About 

 June 15, many plants of the Shepherd's Purse, the Common Winter Cress, 

 and Hedge Mustard {Sisymbrium officinale) were examined in various 

 localities near the insectary. The result was surprising. Scarcely a plant 

 of the last two weeds had not had their roots considerably damaged by 

 maggots ; but not a plant of the Shepherd's Purse seemed to have been 

 attacked by them. That these maggots found at the roots of these weeds 

 were the Cabbage Root Maggot was shown by breeding the insect in cages 

 on the weeds, and also by transferring maggots from the weeds to cabbage 

 plants and producing the typical Cabbage-fly in both cases.* 



These experiments thus show that the Cabbage Root Maggot 

 has several wild food- plants to which it can and probably does 

 resort in case none of its, perhaps preferable, cultivated food- 

 plants are grown in the locality. Doubtless the pest also breeds 

 upon the roots of several other common species of the Mustard- 

 like weeds, some of which may be more common in certain local- 

 ities than either of the two upon which we have found the mag- 

 gots common about Ithaca. Probably the natural food-plants of 

 this pest are some of the Mustard-like weeds, many of which have 

 been introduced here from Europe ; and one may thus expect to 

 find the Cabbage Root Maggot wherever these weeds occur. 



It is remarkable that no one seems to have discovered these 

 maggots on these weeds, nor have suspected that the Cabbage 

 Root Maggot might breed upon such plants. That they do thus 

 feed upon weeds is in itself an important fact, but we believe it 

 will serve to explain other more important points in the life his- 

 tory of the pest which have heretofore puzzled observers. 



To briefly summarize this detailed account of the food-plants of 

 this pest, we may say that it has been recorded in Europe on the 

 cabbage (including the cauliflower, borecoles, etc.), the radish 

 {Raphanus sathms and radiola), the turnip {Brassica rapd), the 

 ruta baga and swedes {Brassica campestris), and on stocks {Mat- 

 thiola) ; the reported feeding on clover roots and manure needs 

 further confirmation. In this country the Cabbage Root Maggot 

 feeds upon most of the above plants and on at least two common 

 Mustard-like weeds, the Common Winter Cress {Barbarea vul- 

 garis), and the Hedge Mustard {Sisymbrium officinale) ; the 



*One of the Fringed Anthomyiians (Phoibia fusciceps) was bred from a maggot found 

 on the roots of the Hedge Mustard (S. officinale). 



