206 THE CANADIAN ENTOMOLOGIST. 



must therefore have been very limited at that period. But when wheat 

 was introduced and became extensively cultivated, it gave them such an 

 ample supply of most palatable nourishment that they have gradually in- 

 creased, and are now excessively numerous, laying every wheat field under 

 contribution for their support." Is it not obvious that the same course 

 may have happened with the Hessian fly ? The more so since just at the 

 time of its appearance in Long IslanH and the adjoining country, the cul- 

 ture of wheat was prominently advanced. Since we know that at the 

 Utmost during six weeks in the year only is the importation of the fly pos- 

 sible, such an importation to America before the discovery of steamships 

 is almost inconceivable. Even if purposely undertaken with all care such 

 an importation would almost surely have been a failure. 



Dr. Wagner has felt the strength of those arguments, and supposes 

 that importation had been possible only from the nearest coast of 

 France. He believes that the lesser distance, as well as the frequent 

 trade with France, makes it more probable. But why not accept that the 

 fly was indigenous here as well as in the old world ? There are Diptera 

 identical with European species, which nobody would think to have been 

 imported. I may mention the common Trichocera regelationis, which belongs 

 to a related group. The species is common here, and was observed by 

 me 13 years ago. But last winter I had specimens sent me from Maine, 

 stating that this insect had never been seen there before, and had been 

 extremely troublesome. I know well that many animals — higher and lower 

 ones — have been imported, because the facts are well recorded ; I believe 

 that a number of others have also been imported, for which the facts are 

 not recorded. But I see no reason to go farther, and am prepared to 

 accept that the same species in both countries may have been developed 

 under similar conditions. I consider, therefore, the Hessian fly to be an 

 indigenous American insect, and not imported by Hessian troops. 



A few words more concerning the periods of unusual abundance of the 

 fly. I was very much interested in the study of the table given by Ur. 

 Packard, but I arrived at the conclusion that the table is not sufficient, 

 and indeed is considered by Dr. Packard himself as very imperfect. 

 Concerning N. England Dr. A. Fitch's statement has been overlooked, 

 Regs, viii., p. 203, that the fly was very injurious in Bercks Co., Mass., 

 in 1779. 



The year 1823 for Maine, and 1S57 for Ohio, are not marked at all 

 in the table, and both the records state that the farmers had ventilated 



