SERPHOID AND CHALCIDOID PARASITES OF THE HESSIAN FLY 93 



and discussed its oviposition habits and importance. In 1885 Forbes 

 treated it under the generic name Semiotellus, described the adult in 

 some detail, and discussed briefly its life history. At the same time 

 he described as Pteromalus fulvipes a rudimentary-winged parasite 

 of the fly, this being the first recognition as a distinct species of this 

 rudimentary-winged form which Say, Herrick, and others had con- 

 sidered to be a form of destructor. In the same year Riley trans- 

 ferred destructor to the genus Merisus, where it still remains. Riley 

 also recognized as a distinct species the short-winged parasite of the 

 fly, which he described under the name Merisus subapterus. 



In a treatise on the parasites of the hessian fly in Russia, pub- 

 lished by Lindeman in 1887, Merisus destructor (Say) is mentioned 

 as a parasite of the fly in North America. Lindeman states that 

 he at first identified as this species specimens reared from the hessian 

 fly in Russia, but that upon comparing them with Riley's redescrip- 

 tion of destructor he decided that they were not that species but a 

 new species which he described under the name Merisus intermedins, 

 so called because it seemed to represent a species intermediate between 

 M. destructor (Say) and M. subapterus Riley. At the same time 

 he characterized two alleged varieties of intermedins, one of which 

 he called rufiventris and the other microptera. Enock recorded 

 Merisus destructor from England in 1888, and Riley the same year 

 identified material from England as M. intermedins. Both Ashmead 

 and Marchal in 1897 recorded M. destructor as parasitic upon Maye- 

 tiola avenae (Marchal), Cecidomyia tritici Kirby, and Phytophaga 

 destructor Say in France. The following year Osborn stated that 

 the species occurred not only throughout the American territory af- 

 fected by the fly but also in England and continental Europe. It 

 was recorded from Canada in 1899 by Fletcher under the name 

 Baeotomus destructor. 



Pospjelov in 1900 stated that Russian parasites of the fly could 

 as well be placed in Merisus destructor as in M. intermedins. He 

 evidently believed these two species to be identical, although he did 

 not definitely say so, and he treated the species under the latter 

 name. The 1900 edition of Smith's Catalog of the Insects of New 

 Jersey listed the species as Micromelus destructor. Felt in 1902 

 referred to Merisus destructor as one of the most efficient parasites 

 of the fly and stated that it occurred in Europe as well as in North 

 America. In 1913 Kurdjumov, after a personal study of Lindeman's 

 types in the Rural Economy Institute at Moscow, stated that he was 

 firmly convinced that Merisus destructor (Say) and M. intermedins 

 Lindeman were identical but noted that he also found representa- 

 tives of Eupteromalus arvensis Kurdjumov among these types. 

 C. M. Packard in 1916 gave what is probably the most comprehen- 

 sive account of the life history of M. destructor. Collin in 1918, 

 and Meyer in 1923, recorded it as a parasite upon Oscinella frit, and 

 the latter author in 1929 again referred to it as a parasite of the 

 frit fly and the hessian fly and also named Elachyptera cornuta as 

 one of its hosts. Other references to the species cited in the bibliog- 

 raphy are for the most part either mere mentions of it or brief 

 reviews of the work of others. 



The writer has studied both European and American specimens 

 of Merisus reared from the hessian fly. The European material ex- 



