Feb. 2, 1920 European Frit Fly in North A merica 47 1 



KNOWN FOOD PLANTS 



The following list of food plants includes those known for the United 

 States and Canada. An asterisk (*) indicates that the fly was reared 

 from this host by the writer. Numbers after authorities refer to the 

 literature cited in this paper. The unpublished references are based on 

 material identified by the writer. 



*Wheat (stems). Garman (70), Fletcher (8), Webster (21), and Coquillett (4). 



Wheat ("roots of wheat"). C. N. Ainslie, Moravia, Iowa (unpub.). 



*Oats (stems). Webster (21), J. J. Davis, Sheldon, 111. (tmpub.). 



*Oats (kernels). 



*Barley. 



*Emmer. 



*Rye. 



GDm (green cornstalks). Tucker (20). 



*Timothy {Phleum pratense). 



*Meadow fescue (Festuca elatior). 



Kentucky bluegrass {Poa pratensis). Fletcher {8) and Webster (l5). 



Slender wheat-grass (Agropyrum tenerum). Fletcher {8). 



Awned wheat-grass {Agropyrum caninum). Fletcher (8). 



Quack grass {Agropyrum repens). Fletcher {8). 



Rye grass {Elymus canadensis). Fletcher {8), and C. N. Ainslie, Elk Point, S. Dak. 

 (unpub.). 



Slough grass {Spartina michauxiana) . C. N. Ainslie, Elk Point, S. Dak. (unpub.). 



Barnyard grass {Echinochloa crusgalli). Webster {21) arid C. N. Ainslie, Elk Point, 

 S. Dak. (impub.). 



Low love-grass {Eragrostis minor). Webster {21). 



Sedge {Cyperiis strigosus). A. F. Satterthwait, La Fayette, Ind. (unpub.). 



Cucumber roots. Webster {21). 



Strawberry. Webster {21). 



Ironweed {Vernonia noveboracensis). Wintering in seed capsules, Webster {21). 



The last three records are the only ones on dicotyledons. It should be 

 noted that the determinations were made at a time when the species of 

 Oscinis were but little known, therefore they may be errors of identifica- 

 tion or of observation. 



PARASITES 



Webster {21, p. 56) mentions having reared Cyrtogaster occidentalis 

 Ashm. from either Oscinis carbonaria, O. soror, or O. umbrosa Loew, in 

 Indiana. His uncertainty illustrates a common difficulty in rearing 

 parasites from these forms. When material is taken from garden or field 

 and placed in a cage to get the parasites, it is likely to contain the Hes- 

 sianfly, Isosoma, Meromyza, Elachiptera, and several species of Oscinis. 

 Although Oscinis frit may predominate, it is impossible to say positively 

 that it was the host of the parasites. These are usually abundant. Even 

 to isolate selected larvae would not entirely obviate the difficulty, since at 

 present no way is known to distinguish those of several species of oscinids. 

 Parasitized larvae would yield no adults, so there could not be a positive 

 determination. Where cages are started by introducing adults on 

 young wheat plants grown under cover, of course no parasitism is 



