Gr. 8. GtRah am-Smith 
543 
Addendum. 
The following experiment, carried out under the most natural con¬ 
ditions possible, confirms the observations on the wintering habits of 
flies quoted previously. Throughout the fly season of 1915 flies were 
allowed to deposit their eggs on small masses of human excrement and 
on animal remains placed on an area of ground 6 x 15 feet surrounded 
by boards sunk vertically into the ground. In the early spring of 1916 
a mosquito net cage was constructed over this area. The flies which 
emerged and were caught in this net could not have hibernated, but 
must have passed the winter as pupae, or in some cases as larvae, in 
the ground, under natural conditions. Several hundreds of specimens 
belonging to the species enumerated below emerged in the following 
order up to June 2: F. scalaris, C. erythrocephala, A. radicum, F. cani- 
cularis, T. canescens, B. serrata, S. stercoraria, D. fiaveola, N. cylindrica, 
P. vulgaris , C. comitoria, H. dentipes, S. carnaria, M. lucorum, L. caesar, 
L. sericata, P. erratica, 0. leucostoma and P. lardaria. 
While in 1915 only 17 flies emerged in “Tin II’’ (p. 443) and about 
90% of the puparia were parasitised (p. 535), in 1916 (see p. 445 and 
Table I) from a very large number of pupae 1876 flies have appeared 
indicating a lesser degree of parasitism. 
On Feb. 29, 1916, certain unruptured puparia, kept under observa¬ 
tion since the autumn of 1914 and known to contain chalcid larvae, 
were placed in jars in rooms B and E (see p. 456). The jar in room E 
contained 16 puparia, each in a separate tube. On April 25 two large 
male pteromaline chalcids emerged from one puparium. Between May 6 
and 19 Melittobia acasta emerged from twelve puparia, three puparia 
contained 2$, another 3$, another 5$, another 8$, two 10$, another 1<J 
and 1$, two Id and 5$, and another one living d, two dead d and 43$. 
In each case after the emergence of the chalcids the puparium was care¬ 
fully dissected. In four instances a few living chalcid larvae, and in one 
living chalcid pupae were found. All these puparia had been para¬ 
sitised previously by A. manducator. Two of the three remaining 
puparia contained dead fly larvae, and the third dead chalcid larvae. 
In room B, at a much lower temperature, 341 similar puparia have 
been kept, but up to June 2 no specimens of M. acasta have emerged. 
On that date some of the puparia were opened, and found to contain 
chalcid pupae. 
Three puparia, containing larvae of M. acasta, were opened in 
December, 1915. and kept under observation in room B. The larvae 
35—3 
