62 Observations on the Habits of Certain Flies 



Winter Observations. 



The winter search for flies in immature stages in natural situations 

 was started in January 1916 and was continued during the whole winter 

 of 1916-1917. Between January 27th and April 20th, 1916, 14, and 

 between September 22nd, 1916, and April 23rd, 1917, 31 hkely places 

 were examined, 45 in all. Of these, 13 were horse manure heaps or near 

 horse manure; 12 were in or near cow manure heaps; 4 in or near horse 

 and cow manure mixed; 6 in or near pig manure; 1 in fowl manure; 

 3 in ash middens; 1 in a refuse pit; 1 a town road-scrapings tip; 1 in 

 ground in corner of a slaughter-house yard; 1 in soil under a spot over 

 which human faeces had been exposed during the previous autumn; 1 in 

 soil under a spot over which cow manure had been similarly exposed; 

 and 1 in the nests of House-martins and Pigeons in an old mill. 



Thirty-seven of these places were in Cambridgeshire, 7 in Norfolk 

 and 1 in Argyll: 29 were in the country and 16 in the town of Cambridge. 



Besides the larvae and pupae collected from these sources, some were 

 taken from cow manure and others from the neighbourhood of horse 

 manure, which had been exposed during the previous autumn in the 

 course of other experiments. 



The only observations of this nature heretofore recorded are those of 

 Graham-Smith (1914 and 1916) and of Bishopp, Dove and Parman 

 (1915). The former examined soil near manure heaps in Cambridgeshire, 

 England, on March 28th, 1914, and, in damp soil under a hedge near one 

 heap, at a depth of about 6 inches, found several pupae of Calliphora 

 erythrocejjhala and one of Ophyra leucostotna; and "in soil close to another 

 heap, which was situated in an open field " a number of pupae from which 

 AiUhonif/id flies eventually emerged. 



Bishopp, Dove and Parman, working at Dallas and Uvalde, Texas, 

 found considerable numbers of House-fly larvae in chicken manure in 

 poultry houses in mid-winter, where they consider the conditions 

 "especially favourable for the immature stages to pass the winter, as 

 the manure generated very little heat, yet being within the chicken 

 house the insects are not subject to excessive cold." They also found 

 great numbers of larvae in Livery barns, which furnished similar con- 

 ditions, "in cracks in the floors and in corners of the stalls." 



Mclhoils employed. 



The larvae were always taken to the laboiatory in some receptacle 

 supplied with holes to admit a plentiful supply of aii', placed in jam jars 



