528 Observations on Habits and Parasites of Common Flies 
whereas one from which A. manducator has emerged is lined by a thick, 
yellowish, tough membrane, leaving a ragged edge when torn. Puparia 
containing shrivelled or moist decomposing fly remains are very brittle 
and unlike those which contain braconid larvae. 
Large numbers of puparia ruptured in both these ways were found 
and counted, but besides these there were also found puparia which 
showed no signs of any opening, and many others, each perforated by 
a minute, round hole like a pin-prick. In the former either the shrivelled 
remains of fly pupae or living chalcid larvae were found, and in the 
latter some dead chalcids, and dry, dusty fragments on which numerous 
small mites, apparently Tyroglyphus siro, were feeding. The examina¬ 
tions of the puparia revealed much that was of interest and worthy of 
detailed record. 
A. In the “shade box” the remains of 2778 puparia were found. 
From these 1067 flies (987 blow-flies, 58 F. scalaris, 10 H. dentipes, 
12 T. canescens) had emerged, 9 puparia contained shrivelled, moist 
or decomposing fly remains. 1324 braconids had emerged and had 
been caught, 66 puparia contained dead braconids, and from 304 puparia 
braconids had emerged and escaped. Lastly five puparia contained 
living braconid larvae, and three were being eaten by unknown larvae. 
Therefore of all the pupae originally in this tin 61 % had been para¬ 
sitised by braconids. The examination of the pupae in May revealed 
the interesting fact that the large braconids which had appeared previous 
to that time had emerged from the largest puparia, almost all of which 
were empty. The smaller specimens of the same species which emerged 
in the autumn came therefore from the medium sized and smaller 
pupae. 
B. As previously stated a batch of pupae were transferred from 
this box to the “sun tin” on April 29 and kept there in a separate jar. 
This jar, on examination in November, was found to contain 293 puparia. 
From these 17 flies (14 blow-flies and 3 H. dentipes) had emerged, 28 
puparia contained shrivelled or putrifying fly remains, 60 braconids 
had emerged, 4 puparia contained dead braconids, 23 puparia showed 
pin-holes and contained dead chalcids, and 161 puparia were whole 
and contained chalcid larvae. In this jar therefore 21-8 % of the 
pupae were parasitised by braconids and 62-6 % by chalcids. Since 
no chalcids were present in the original stock of pupae it is clear that 
the parasitism by the chalcids took place after the transferred pupae 
were placed in the “sun tin.” 
C. In the “sun box” the remains of 971 puparia were found. 
