58 Observations on the Habits of Certain Flies 



Copeman and Austen (1914), Graham-Smith (1914 and 1916), Bishopp, 

 Dove and Parman (1915) and Dove (1916)i. 



As early as 1908 WilHston stated that the M'inter was passed in the 

 puparia, but that in secluded spots mature flies will sometimes survive 

 the winter. He does not, however, quote any experiments to qualify 

 these statements. 



Howard (1911) wrote that M. domestica hibernates ''in the puparium 

 condition in manure or at the surface of the ground under a manure heap. 

 It also hibernates as adult, hiding in crevices": and in 1912 "Adult flies 

 undoubtedly linger in warmed houses throughout the winter, but that 

 enough of them remain in active condition in such locations to per- 

 petuate the species and start the rapidly multiplying generations of the 

 following summer seems doubtful " ; but thinks it very probable that the 



1 Since the Preface and account of my observations on the Wintering habits of Hies 

 were written, two papers have been read, the authors of which claim to have successfully 

 bred M. domestica from over- wintered pupae: and, furthei', certain of their observations 

 are of interest in connection with my Burial Experiment, pp. 80-84. 



I. Kisliuk (1917) found that (1) flies which are not kept cold enough to become in- 

 active (see Dove, 1916) will either oviposit, if the temperature is high enough, or die com- 

 paratively soon; (2) under natural conditions neither eggs nor larvae are to be found alive 

 in normally preferred situations, though the latter may probably be found in early winter 

 (these observations were made in America, but the latter one does not tally with those 

 made by Graham-Smith (1916), McDonnell and Eastwood (1917) and my own (1916-1917) 

 described in this paper, when larvae of various flies were found throughout the winter). 

 (.'}) From pupae collected from natural situations on February 2(i, a few flies emerged on 

 March 10th-]2th, though 91 per cent, were parasitised, which, he considers, indicates that 

 M. domestica hibernates as a pupa. And from breeding experiments he concluded that the 

 following species hibernate in immature stages: L. sericata, L. caesar, L. sylvarum, Fhormia 

 regina, C. erythrocephala, C. vomitoria, Cynomyia cadaveriiia, and P. rudis, which also does 

 so as an adult. 



II. McDonnell and Eastwood (1917) made the following observations: (1) "On Maich 

 .3rd, 1917, living larvae were found in a heap of old manure at a depth of :} feet. 

 This heap had not been touched since October 1916 and was overgrown with grass and 

 weeds. On March 20th larvae were found at a depth of 2 feet in a mixture of dry earth 

 and human excreta, which had beim made in September 1916, and was covered with a 

 6 inch layer of earth". (2) "Larvae found at a depth of 2 feet in a manure heap were 

 apparently dead, but revived, when exposed to heat. Evidently they were hibernating." 

 (3) Pupae, which had migrated from the manure in the larval state, were found 2 feet 

 from their respective dumps at a depth of about an inch below the surface. (4) The larvae 

 nearly all pupated within 24 hours of removal from the manure heap, but one or two were 

 still persisting as larvae on April 14th. (."")) During first week in A])i'il pupae developed into 

 flies — F. caniculuri.s and M. domestica. 



From these observations the authors conclude that, as living lly larvae were fouiul. in 

 March, in earth and human exci-ement made six months previously, reliance cannot always 

 be plac(!d in thi' mctliod of disposal in shallow trench latriiu's as a preventative of lly 

 breeding. 



