232 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 2 



Ministry of Agriculture of Russia, St. Petersburg, wrote to us as 

 follows relative to this species on quack in his country : - ' Several 

 Russian naturalists (Portschinsky, Jaroschewsky, Philippiew, Linde- 

 mann) have several times found the larvse of this species in numbers 

 on the stems of Agropyron repens. We consider this plant as natal 

 for this insect." 



Prof. F. M. Webster wrote to the author in these words: "With 

 regard to your breeding Hessian fly {Mayetiola destructor) from 

 quack grass, I will say that it seemed to breed freely in Agropyron 

 in Kansas last year, very evidently originating from serious out- 

 breaks of the pest in adjacent fields of wheat. In order to make 

 sure, the species will need to be bred from Agropyron to wheat and 

 those from wheat bred from Agropyron. Wlien this has been done, 

 all obscurity, it seems to me, relative to the occurrence of Hessian fly 

 in grasses wall be swept away. ' ' 



We believe that the determination of specimens taken in native 

 grasses has never before been corroborated by biological criteria. We 

 can now say wdth certainty that the true Hessian fly can breed freely 

 in quack at least under some conditions. It is therefore important 

 to know more about these conditions. Evidently they will breed most 

 readily in grass that is young and tender in the fall at the time of 

 oviposition. Since quack is a noxious weed almost everywhere in 

 the United States, it is unfortunate to have to regard it as even a 

 possible source of infestation. It is not likely, however, that the fly 

 is usually plentiful enough in quack to make it a dangerous source 

 of trouble from, a practical point of view, except possibly in rare 

 instances. If it were generally so numerous in this grass, one would 

 expect it to be well kno^\^l at this late date. 



The question can now be raised whether quack was the original 

 host of the Hessian fly which was able to develop more abundantly on 

 the cereals after their introduction by man. If this should be so, 

 then the history of this insect would be a parallel case to that of the 

 Colorado potato beetle. If Agropyron could be found infested with 

 Hessian fly in regions remote from cereal crops, we would consider 

 it the original host. In this case the insect might have been native 

 anywhere in the temperate regions where the circumpolar Agropyron 

 grows. There would then be no mystery about its introduction in 

 America. But this must be considered a profitless subject for specu- 

 lation, unless the nativity of the insect on quack should be tested as 

 above suggested. 



The following is a brief summary of the observations by others on 

 the supposed Hessian fly in native grasses: 



