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 anthomyiarum, 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 Masca 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 
