360 
Parasites of Common Flies 
meat, and one specimen of a species of Conostigmus or Lygocerus in May 1916 
from a puparium collected in the autumn of 1915. 
These parasites being very small easily escape observation, and it is 
probable that many species infest the diptera. 
ICHNEUMONIDAE. 
Only 4 Ichneumons were obtained, all from puparia of C. erythrocephala, 
1 d Phygadenon speculator, Thoms, in July 1916 from a puparium collected 
earlier in the season, and 1 $ and 2 $ of Atractodes bicolor Gravenh. in June 
and October 1916 from puparia collected in the summer of 1915 (shade tin). 
Fig. 9. Atractodes bicolor X 12. 
CHA LCIDIDA E. 
Melittobia acasla Wlk. 
Great numbers of fly puparia kept under observation during the winter of 
1914-15 were found to be naturally infected by M. acasta. “Every puparium 
attacked by the chalcid was found to be lined by the thick membrane charac¬ 
teristic of a puparium containing a braconid larva.” These observations have 
been quoted in detail (1916, pp. 532-535). At the time of examination (in 
the winter of 1915-16) a number of intact puparia were discovered from which 
neither flies, braconids nor chalcids had emerged. Some were dissected and 
found to contain living chalcid larvae and remains of braconid larvae, but 
370 were kept for further observation and placed in jars in a warm room E 
and a cooler room B. One jar in room E contained 16 puparia, each in a 
