108 MISC. PUBLICATION 17 4, U.S. DEPT. OF AGRICULTUBE 



scription and is believed to be correctly determined. In the opinion 

 of the writer, therefore, crassinervis Thomson is a synonym of 

 chalcidiphagus Walsh and Eiley. 15 



Both mandibles of chalcidiphagus ( = crassinervis) are 3-toothed, 

 as Masi has correctly pointed out. Since this character does not 

 conform to the genus Homoporus, it seems necessary to accept Masi's 

 proposal of the genus Merisoporus and to call the species Merisoporus 

 chalcidip hagus. 



HOSTS AND LIFE HISTORY 



Merisoporus chalcidiphagus is normally a primary parasite of the 

 jointworm flies. Phillips and Poos have recorded as hosts for it 

 Harmolita tritici (Fitch), vagirdcola (Doane), secalis (Fitch), 

 hordei (Harris), elyrrdcola Phillips and Poos, and atlantica Phillips 

 and Poos, and in Europe it is recorded from H. rossicum (Rimsky- 

 Korsakov). Phillips states that in a single instance he was able to 

 get it to reproduce successfully on Ditropinotus aureoviridis Craw- 

 ford, a primary parasite of jointworms. 



Myers' unpublished manuscript records that on July 12, 1919, a 

 single female of this species was reared from a puparium of Phyto- 

 phaga destructor which he had collected at Mount Holly Springs, 

 Pa., on July 4, 1932. The fly puparium had been isolated in a small 

 capsule immediately after collection, and there appears to be no 

 doubt as to the authenticity of the record. 



This species is a primary, solitary parasite feeding externally upon 

 the jointworms within their galls and develops in the same manner 

 upon the hessian-fly larva within its puparium. Phillips and Poos 

 state that adults appear in the latitude of Virginia in the latter part 

 of May and continue breeding until October. Five complete genera- 

 tions per year may occur. The egg is laid externally upon the host 

 larva within the wheat stem, and the winter is passed as a full-grown 

 larva in the jointworm cell or in the puparium of the hessian fly. 



DISTRIBUTION 



Merisoporus chalcidiphagus is a widely distributed species both 

 in Europe and in North America. European records indicate its 

 occurrence in Sweden, Italy, and Russia. One specimen in the Na- 

 tional Museum collection is from Lille, France, the collector and host 

 not indicated; another specimen determined by Schmiedeknecht is 

 without locality label but probably was taken in Germany. 



In American literature it has been recorded from the States oi 

 Ohio, Illinois, Indiana, Michigan, Kentucky, Tennessee, Missouri, 



is There is some doubt in the mind of the writer as to whether or not chalcidiphagus is 

 really a different species from luniger Nees. Rimsky-Korsakov has recorded both luniger 

 and crassinervis as parasitic upon Harmolita rossicum, these identifications apparently 

 having been made for him by Mayr. In the Mayr collection at Vienna are specimens 

 under botb names which upon a hurried examination seemed to the writer to be the 

 same. The description of luniger as given by Thomson, however, will not apply exactly, 

 with respect to the marginal vein, to any of the material now at hand. In all the speci- 

 mens, both American and European, now available for study, the marginal vein is thick- 

 ened, and in none of them is it over one and one fourth times as long as the stigmal 

 vein. According to Thomson the marginal vein of luniger is not thickened and is one 

 and one half times the length of the stigmal vein. According to Masi, on the other hand, 

 the proportion of marginal vein to stigmal is as 100 : 78 in luniger and exactly the same 

 in crassicornis. There is some variation in the thickness of the marginal vein shown by 

 the specimens at hand, as there is also in the proportional length of marginal and stigmal 

 veins, but the range of this variation does not appear to be sufficient to include luniger as 

 defined by Thomson. If Thomson's description is accurate, then luniger is apparently 

 distinct from crassinervis. 



