SERPHOID AXD CHALCIDOID PARASITES OF THE HESSIAN FLY 113 



Xees' statement as to the identity of bicolor and plagiatus is accepted 

 as correct, and the older name is applied to the species. 



The writer has seen Walker's type of Micromelus rufomaeulatus in 

 the British Museum and found it to agree with the description of 

 Pteromalus plagiatus Xees, a fact first pointed out by Reinhard. 

 M. rufomaeulatus is thus a synonym of Callitula hicolor. 



As already mentioned. Kurdjumov believed Micromelus pyrrho- 

 gaster Walker and Micromelus subapterus (Riley) to be probable 

 synonyms of this species. The type of the former species has been 

 examined by the writer and. although very similar to bicolor, differs 

 from it by having a much thicker head and vestigial wings. So far 

 as is known, the fully winged bicolor has never been associated in 

 any rearings. either in Xorth America or in Europe, with a vestigial- 

 winged form, nor has pyrrhogaster ever been recorded from the 

 hessian fly. In view of these facts it is believed that pyrrhogaster is 

 probably a distinct species. 



Riley's subapterus is a quite different species and is a synonym of 

 Eupteronwlus fvlvipes Forbes, which is treated elsewhere in this 

 publication. 



HOSTS AXD LIFE HISTOBY 



Little seems to be known regarding the life history of Callitula 

 bicolor. It has been most commonly recorded as a parasite of 

 Phytophaga destructor. As already shown, Imms has recorded it 

 as a parasite of Oscinella frit (L.) in England, and Tzuigankov 

 claims to have reared it from Meromyza saltatrix (L.), Lasiosina 

 cinctipes Meig., and Chlorops taeniopus Meig. in Russia. Kurd- 

 jumov states that in studies of the hessian-fry parasites conducted in 

 Poltava this species was always reared as a secondary parasite, and 

 Znamenski makes a similar statement. 



According to an unpublished manuscript of the late P. R. Myers, 

 studies carried out at the Carlisle, Pa., laboratory of the Bureau of 

 Entomology show that the species is normally a primary, external, 

 solitary parasite of hessian-fry larvae of the spring generation. The 

 parasite feeds externally upon the host larva within the host pupa- 

 rium and emerges as an adult from the puparium. In several 

 instances, however, the species was found to have developed as a 

 parasite of Platygaster zosine, and in one instance at the expense of 

 another undetermined primary parasite of the fly. 



DISTRIBUTION 



Callitula bicolor is a widely distributed species both in Europe 

 and in Xorth America. In Europe it has been recorded from Eng- 

 land, France, Germany. Italy, and Kiev and Poltava in Russia, The 

 writer has also seen specimens in the collection of Ruschka at the 

 Xaturhistorisches Museum at Vienna which it is believed were col- 

 lected in Austria. 



In North America this species has been taken in Xew York, Penn- 

 sylvania, Maryland. Virginia, Ohio, Indiana. Michigan, and Xorth 

 Dakota. Records from Pennsylvania embrace numerous localities 

 distributed in at least 10 different counties. Maryland records also 

 include localities in several counties and range from tidewater to the 

 mountainous western part of the State. Records from the other 



6685°— 33 8 



