35H Parasites of Common Flies 
These parasites undoubtedly play an important part in restricting the 
numbers of adult flies which emerge, but hitherto the species parasitic on 
diptera have been greatly neglected. From their economic importance, the 
diversity of their habits, and the peculiarities of their structure, these parasites 
deserve more attention than they have received, and it is with the hope of 
calling attention to them that the following observations have been recorded. 
For the same reason a sketch of each species, showing the appearance of the 
insect, has been inserted. Though such drawings are of no value for determining 
species, they indicate roughly the characters of insects belonging to different 
families and illustrate the remarkable diversities of their forms. 
Many of the genera embrace scores of species most difficult to identify, 
and many species are as yet undescribed. 
Dr R. C. L. Perkins most kindly examined the examples of the Cynipids 
and Proctotrupids, Mr J. Waterston several of the Chalcids, Mr C. Morley the 
Ichneumons and Mr G. T. Lyle the Braconids. Prof. Masi of Genoa, in the 
absence of Mr Waterston, very kindly identified Necremnus leucarthros. 
Fig. 1. Diranchis sp. $. X 20. Fig-2. Kleidotoma sp. X 20. 
CYNIPIDAE. 
Of this family 4 specimens, 2 A and 2 $, of a species of the genus Diranchis 
(Forst) emerged in June 1916 from puparia collected in the autumn of 1915. 
Five specimens, 3 <£ and 2 $, of a species belonging to the genus Kleidotoma 
(Westwood) emerged in June 1917 from puparia collected in faecal material 
in the autumn of 1916. 
A species of the genus Figites emerged in May and June 1916 and 1917 from 
puparia collected in the preceding years and kept under circumstances which 
precluded the possibility of spring infection. It was noticed that they appeared 
from puparia kept outside in a warm situation nearly a month earlier than 
from puparia kept in the shade. Altogether 73, 28 ^ and 45 ?, emerged during 
these two years. The percentage of infection was very small. For example 
from one batch of 4280 puparia from larvae feeding on exposed meat only 
