NATURAL ENEMIES 89 



almost any one of the many species of dipterous larvae 

 found there, and have been reared from the larvae of 

 the horn fly, from several species of true dung-flies 

 (family Scatophagidae), and from others. Two spe- 

 cies, however, are reared from the maggots of the ty- 

 phoid fly. These are Figites anthotnyiarum, reared 

 from the house fly in Germany by Reinhard, and 

 Figites scutellaris, also a European species. If careful 

 rearing experiments were carried out continuously in 

 this country with house fly larvae, it is probable that 

 other species of this group would be reared. Prof. 

 T. D. A. Cockerell, for example, caught one of them 

 Eucoila impatiens Say on horse dung at Las Cruces, 

 N. Mex., in 1894, and suspected its parasitism on house 

 fly larvae (Insect Life, VII, 209). Many similar ob- 

 servations can doubtless be made very easily. 



The Chalcidoid parasites of Musca domestica are 

 more numerous. In the family Pteromalidae there is 

 a genus, Spalangia, which seems practically confined to 

 dipterous larvae. One species, Spalangia niger, was 

 found by the German author Bouche to lay its eggs in 

 the pupae of the house fly and to issue in April and 

 May. The larvae of the Spalangia are spindle-formed 

 and white, almost translucent, and are to be found in 

 the autumn in the puparia of the house fly, where they 

 destroy the true pupae. 



Several species belonging to this same genus are to 

 be found in the United States, and one of them at least 

 has similar habits. Mr. H. L. Sanford, of the Bureau 

 of Entomology at Washington, in opening a series of 



