105 



The Russian Parasite of the Hessian Fly. — Miss Eleanor A. Ormerod, 

 the eminent consulting entomologist of the Royal Agricultural Society of England, 

 in a communication to the Mark Lane Express, thus refers to the discovery of 

 this parasite : — 



" It is announced in the United States that Professor C. V. Riley, the well- 

 ^nown entomologist to the United States Department of Agriculture, has intro- 

 duced into that country living specimens of Semioiellus nigripes, a Russian 

 parasite of the Hessian tly, in order to acclimatize it. By its aid he hopes to 

 practically exterminate the pests in that country. Curiously enough he obtained 

 this parasite from England, and it is said that quite a number have been reared 

 for the purpose. If this is the case, there should be no difficulty in the way of 

 adopting the same means of getting rid of the Hessian fly in this country, and 

 it would be interesting to have Miss E. A. Ormerod's opinion on the subject." 



My opinion is that, quite certainly, it would be worse than useless (in this 

 country) to make any such attempt. In the United States of America things 

 are on a very different footing. There are ditferenoes in temperature, conditions 

 of climate, and also of area of cropping, and other agricultural arrangements 

 which must aflect this question. Likewise there are special arrangements at the 

 Government experimental stations for rearing insects, and skilled Government 

 entomologists who can trustworthily examine the collections before they are 

 turned loose on the country. 



The parasite fly (the Semiotellus nigripes) is only about one! line long, and 

 without the help of a magnifying glass and some technical knowledge it would 

 be impossible for any but skilled entomologists to be certain whether many pests 

 were not included amongst the parasites which they set free. Also it is to be 

 remembered for the most part insects pair, lay eggs, and die very shortly after 

 they make their appearance from the chrysalids, but even supposing these 

 minute creatures lived on awhile, where are they to be taken to ? J 



We do not know what corn is infested until attack is thoroughly set up, for 

 the most part till the mischief is so advanced that the time for action of the 

 parasite is past ; and at a vast expense the intended destroyers would in many 

 cases be carried where there was nothing to destroy. 



This work of rearing could not be done on a broad scale — that is, by collec- 

 tions from the threshing machine by farmers — and the payment to a staff of 

 collectors, rearers, and distributors would involve enormous outlay. 



The present plan of destroying the Hessian fly chrysalids in the fine 

 screenings is much the safest, and also has, for this country, the stated approval 

 of Prof. Riley himself It is easily done, costs scarcely anything, and causes no 

 loss; and thus, though we destroy the parasites (of which there are several 

 kinds), we also quite certainly destroy the pest. 



8 (en.) 



