G-. S. Graham-Smith 
445 
larvae (p. 503). In May, 1915, a few specimens of H. dentipes emerged, 
and on Aug. 31 two house-flies were seen which seemed to be freshly 
emerged. 
In view of the very small number of flies, the late period of the season 
at which they were seen, and the possibility, though small, of their 
having gained entrance to the cage from outside, the experiment cannot 
be regarded as convincing and it is being repeated under conditions 
which, it is hoped, will prove satisfactory. 
The only other experiment of the kind carried out by Bishopp, Dove 
and Parman (1915) near Dallas, Texas, bears a great resemblance to 
the one just quoted. These observers put “ about three barrels of mixed 
horse manure and cow manure, and straw infested with considerable 
numbers of larvae of all sizes andpuparia into a cage” on Nov. 26,1913. 
The manure pile was covered by high water in December and no 
adults were seen after Dec. 27. Four adults appeared on April 16, 
1914. “During the latter part of April and early May the manure 
was again submerged on account of heavy rains, and during this period 
observations were not made. It seems certain that some larvae were 
killed by these inundations. However, on May 26, six very vigorous 
adults were found in the cage. Observations on emergence were not 
made for some time after this.” 
“We thus have shown that the house-fly lived in the larval and 
pupal stages from Nov. 26,1913, to May 26,1914, a period of six months.” 
In order to supplement the information obtained during the previous 
year, similar experiments were carried out during the winter of 1915-16, 
in the “ tins ” and cages of the type described, and the larvae and 
pupae present were examined at various times. 
In the two “tins” numerous pupae, mostly of C. erythrocephala, were 
present early in November, but many larvae continued to feed up to 
Dec. 31, and were seen feeding on warm days even later (Jan. 14). 
By Feb. 14 the larvae had left the food, and were seen amongst the 
pupae in the earth at the bottom of the tins. They lay still, but moved 
on being touched, or when light fell on them, and if brought into a 
warm room became quite active. On Feb. 20 many larvae and recently 
formed, bright coloured pupae were seen, and a few larvae were still 
present up to March 30. Cold weather in the autumn probably checks 
the feeding and growth of the larvae, but does not prevent their 
ultimately becoming full-fed, pupating, and emerging as flies (see p. 446). 
In the exposed “ tin ” during November and December the minimum 
temperature fell below 32° F. on twenty-three nights, and on one 
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