INSECT PARASITES 169 



There is no doubt, jndcring fi-(jiii the numerical abundance of 

 the above parasites which the authors indicate in their papers, 

 and from my own observations in the case of another species of 

 Pteromalid, that these parasites are of importance in h(jlding 

 M. domestica in check where the parasites are sufficiently abundant. 



In addition to the many Chalcid parasites of M. domestica, a 

 number of parasites belonging to the family Cynipidae have been 

 reared from the house-fly. Most of the Cynipidae are minute 

 gall-forming insects, causing some of the well-known galls on 

 plants such as the oak galls. One sub-family, the Figitines, 



Fig. 76. Figites sp. Muscicl parasite, x 28. 



however, are parasitic on the larvae of insects, having been ob- 

 tained from dipterous, neuropterous and coleopterous larvae, and 

 they do not attack plants. These insects are described by Kieffer 



found was 9 Spalangia larvae and pupae from 22 puparia. He found two genera- 

 tions, and a third more or less in-egularly, each year in Massachusetts. The winter 

 is probably passed in the pupal stage and the parasites emerge in the spring. The 

 second and strongest generation emerges during late July or August, while a third 

 may appear late in September or early October. 



Bishopp (1913) found .S'. nniscidariim a parasite of M. domestica, Stonioxys calci- 

 trans and Haematobia serrata in Texas. 



Pinkus (1913) studied the life-history and habits of Spalangia muscidanim as a 

 parasite of S. colcitrans at Dallas, Texas. The parasitism of 31. domestica was 

 also studied and he discusses the possibility of the artificial propagation of the 

 parasites. 



