SERPHOID AND CHALCIDOID PARASITES OF THE HESSIAN FLY 107 



REVIEW OF LITERATURE 



Semiotellus chalcidiphagus was first described and figured by 

 Walsh and Riley in 1869 from specimens reared from galls of the 

 barley jointworm, Harmolita hordei (Harris), collected in Canada. 

 The following year Walsh gave a more complete technical descrip- 

 tion of the species accompanied by the same figures and stated that 

 the material originated at Grimsby, Ontario. Cresson in 1887, 

 Provancher in 1889, and Ashmead in 1890 listed the species, and 

 Webster in 1892 and again in 1893 mentioned it as an important 

 parasite of the jointworm. In Smith's Catalog of the Insects of 

 New Jersey, published in 1900, Ashmead transferred the species 

 to the genus Homoporus, and subsequent writers have used 

 that combination, with the exception of Viereck, who listed it as 

 Merisus (Phaenacra) chalcidiphagus in the catalog of the Hymen- 

 optera of Connecticut. Webster, as well as Phillips and Poos, pub- 

 lished additional articles in which they mentioned this species as 

 parasitic upon one or another of the jointworm flies. The most 

 important of these papers is that by Phillips and Poos in 1921, 

 which gives in detail descriptions of the egg and larva, a list of 

 the hosts attacked, and an account of the life history. 



Meanwhile in 1878 in Europe Thomson had described Homoporus 

 crassinervis from specimens collected in Sweden. In 1914 Rimsky- 

 Korsakov, writing on the jointworm flies of cereals and their para- 

 sites in Russia, recorded H. crassinervis as a parasite of {Isosoma) 

 Harmolita rossicum (Rimsky-Korsakov). In 1924 Masi erected the 

 new genus Merisoporus for the reception of Homoporus luniger 

 Thomson and H. crassinervis Thomson, separating the new genus 

 from Homoporus by the fact that in the former both mandibles are 

 3-toothed whereas in the latter both are 4-toothed. The following 

 year Ferriere and Faure included the species in a key to the species 

 of the genus Homoporus, and in 1929 Meyer again listed it as a 

 parasite of Harmolita rossicum in Russia. 



On the occasion of a visit to European museums in 1927 the writer 

 found at the British Museum that the late James Waterston had 

 obtained, through the good offices of B. Uvarov, the loan of the mate- 

 rial upon which the paper by Rimsky-Korsakov dealing with the 

 joint- worms of cereals and their parasites in Russia had been based, 

 and that among the parasites were specimens labeled "Homoporus sp." 

 Specimens of Homoporus chalcidiphagus reared from jointworms in 

 North America were compared with these Russian specimens, and 

 in the opinion of both Waterston and the writer they proved to be 

 the same species. Later the writer was privileged to study, in the 

 Natural History Museum at Vienna, the collections of Mayr and 

 Ruschka. Under the name H. crassinervis specimens identified by 

 Mayr were found, the labeling of which showed that they had been 

 reared from jointworm material by Rimsky-Korsakov. These speci- 

 mens also agreed in every way with the American species. The 

 United States National Museum possesses one female specimen de- 

 termined by Schmiedeknecht as crassinervis, which differs in no way 

 from the above-mentioned material. The type of H. crassinervis, 

 which is probably at Lund, Sweden, was not seen, but the material 

 studied, both American and European, agrees with Thomson's de- 



