f% (faatoin Entomologist. 



VOL. XX. LONDON, JULY, 1888. No. 7 



THE HESSIAN FLY AN IMPORTED INSECT. 



BY DR. C. V. RILEY, WASHINGTON, D. C. 



As the readers of the Canadian Entomologist are aware Dr. H. A. 

 Hagen has argued at length to the effect that the Hessian Fly was, first, 

 not imported by the Hessian troops ; secondly, that it was not imported 

 from Europe at all, and that it is an indigenous North American insect. 

 In the Third Report of the U. S. Entomological Commission, Dr. Packard 

 has an extended article upon the Hessian Fly, and while he alone is 

 responsible for the general position there taken on this subject, we dis- 

 cussed the matter together, and the views there presented are substan- 

 tially those which I held at the time, as it was Dr. Packard's desire to 

 arrive at an impartial judgement. The subsequent communication of Dr. 

 Hagen in the Canadian Entomologist for May, 1885, seemed, however, 

 positively to set at rest the question of the introduction of the insect by 

 the Hessian troops, as well as of its occurrence in this country prior to the 

 revolution ; because the correspondence which he there published from 

 Mr. H. Phillips, jr., seemed to admit of no further doubt that the first 

 question was settled in the negative, and the second in the affirmative. 

 While in Europe last autumn, I found a great deal of interest manifested 

 in the subject of the Hessian Fly in England, on account of its recent 

 introduction there, and, being called upon, I made some statements at 

 one of the meetings of the London Entomological Society, which will be 

 found reported in the Transactions of the Society for October 5, 1887. 

 I take the liberty of quoting therefrom the following passages as indicating 

 my position in the matter : 



" Prof. Riley said it would extend his observations beyond reasonable limits, to 

 enter into the details on which he based his own conviction, which had been substantially 

 expressed in the full paper by Packard, in the ' Third Report of the United States 

 Entomological Commission (1883).' His opinion was that while we might drop the 

 Hessian theory — since Mr. Henry Phillips, jr., as quoted by Hagen (1885), finds mention 

 of the ' Hessian Fly,' in the unpublished minutes of the American Philosophical Society 

 for 1768 (a rather astonishing fact, as it antedates the landing of the Hessians !), — and 



