A NEW AMERICAN PARASITE OF THE HESSIAN FLY 

 (MAYETIOLA DESTRUCTOR SAY). 



By P. R. Myers, 

 Of the Bureau of Entomology, United States Department of Agriculture. 



During the course of some biological investigations of the parasitos 

 of the Hessian fly, MayeiiGla destrudor Say, by Mr. W. R. McConneU 

 and the author, a parasite new to America was reared from puparia 

 in great abundance. This parasite runs to Polygnotus Focrster in 

 Ashmead's key (Monograph of the North American Proctotrypidac). 

 It was compared with specimens of European Proctorypoid para- 

 sites of the Hessian fly in the United States National Museum collec- 

 tion, some of which are labeled Platygaster minuivs Lindeman and 

 others, Polygnotus (Platygaster) minutus Lindeman. This European 

 material represents two distinct species. The specimens labeled 

 Platygaster minutus Lindeman were sent from Russia and are prob- 

 ably paratypes of Lindeman's species. These specimens are closely 

 related to our Polygnotus Memalis Forbes but are distinct from those 

 labeled Polygnotus (Platygaster) minutus Lindeman and the new 

 species described in this paper. The specimens standing as Polyg- 

 notus (Platygaster) minutus Lindeman are labeled "France" and were 

 probably determined by Ashmead. One of these specimens has 

 "zosinef" written at one end of the label. These specimens aro 

 apparently the same as the specimens described as a new species in 

 this paper. This new parasite will be found to compare somewhat 

 favorably with the original description of Platygaster zcsine Walker, 

 but his description is too brief and indefinite to enable the writer to 

 determine whether or not the material before liim represents W^alker's 

 species. Because of the difficulty encountered in securing authorita- 

 tively named material or having com.parisons made with the types of 

 European species at the present time on account of the unsettled 

 conditions in Europe, it has been decided to describe this American 

 Hessian fly parasite as a new species, since it is necessary that wo 

 should have a specific name for use in the notes relating to our inves- 

 tigations. In the writer's opinion, this new parasite may prove to 

 bo Platygaster sosine Walker, and in that case it was probably intro- 

 duced by in Riley 1891 with Pleurotrojns (Entedon) ejngonus (Walker) 

 Riley, if indeed it- had not already been introduced previous to that 

 time. 



Proceedings U. S. National Musdum. Vol. 53-2204. 



255 



