376 
Parasites of Common Flies 
Stenomalus muscarum. 
This chalcid was not obtained from fly puparia, but in view of the fact 
that it has been found hibernating in company with flies on several 
occasions some observations on its seasonal prevalence may be of interest. 
In 1916 large numbers were present on the windows on March 3 and 18. 
Few were noticed during the summer, but hundreds were observed on the 
windows on September 27 and 28, October 1 and 2, and November 15. In 
1917 a few were noticed on the windows on April 7, 20 and 29 and very 
large numbers on September 6, 24 and 29. In 1918 they were numerous on 
the windows on March 25. Attempts were made to induce females to oviposit 
in fly puparia, but without success. 
Fig. 19. Stenomalus muscarum $. x 20. 
BRACONIDAE. 
Alysia manducator. 
A. manducator has been obtained in considerable numbers each year from 
several series of fly puparia bred under natural conditions. 
The observations made in 1915 and previously recorded (1916, p. 524) 
showed that numerous specimens of A. manducator emerged from puparia 
collected from shady situations in the autumn of 1914. A small batch con¬ 
sisting of 209 specimens appeared in the spring of 1915, and after an interval 
of three months a second and larger batch of 1115 specimens, being 83 per cent, 
of the total number. Of all the puparia collected 61 per cent, were infected by 
this parasite. Further it was shown that the time of emergence in the spring 
