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PARASITES OF THE "HESSIAN FLY" 

 (Cecidomyia destructor, Say). 



By Eleanor A. Ormerod, F.E.S. 



So much has been written during the past season relatively 

 to the species of the parasites of Cecidomyia destructor, Say, 

 which we have found present amongst us in this country, that it 

 may be of interest to many of your readers to know that the 

 opinion lately expressed by Prof. C. V. Riley (Entomologist of 

 the United States) that these parasites would probably be found 

 to be Russian, or of European origin, has been recently confirmed 

 by Dr. Ch. Lindeman, Professor at the Academy of Agriculture, 

 Moscow (whose works on Hessian fly and its parasites are too 

 well known to require comment), who has recently named four 

 species out of a collection of parasites which he had permitted 

 me to forward him, as being Russian kinds. 



In a letter lately received from him, Dr. Lindeman informs 

 me that amongst the specimens of parasites which he finds 

 amongst those reared from puparia of C. destructor, preserved 

 from what were found on corn grown last year at Daleally, 

 Errol, N.B., by Mr. D. Taylor, there are the following species: — 



Semiotellus nigripes, Lind. 



Tetrastichus 7'ileyi, Lind. 



Merisus hiteiinediiis, Lind., var. micropterus. 



Platygaster mimitiis, Lind. 



These are Russian species, which will be found described at 

 length in Dr. Lindeman's paper, ''Die Pteromalinen der Hessen- 

 fliege {Cecidomyia destructor, Say)"; and Dr. Lindeman has also 

 had the great kindness to send to me a gift of a small collection 

 of the four above-named species, and one variety of these 

 parasites, which I am now having displa^^ed for microscopic use 

 with the utmost care. 



Besides the above species, named by Dr. Lindeman from 

 personal knowledge, he found in my consignment a single 

 specimen, which he writes me agrees well with the description 

 given by Prof. Riley of the American Merisus destructor, Sa}'. 



From the above observations it appears to me that we may 

 look on a part of our visitation of Cecidomyia destructor having 

 been derived from Russia ; and with regard to what may be 

 inferred from the presence of the species commonly known as 



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