86 Observations on the Habits of Certain Flies 



3. The distribution of dipterous larvae in a manure heap in winter, 

 at any rate in the Eastern Counties, is extremely local and, therefore, 

 calculations based upon the number of larvae or pupae per pound of 

 manure are futile. 



4. Usually there seemed to be little preference shown by the larvae 

 for any particular part of the heap, but in a few cases they seemed to 

 select the portions which received least light. 



5. During- the summer and autumn M. domestica was found in 

 largest numbers, in town and in the country, in the neighbourhood of 

 horse manure — in the latter case in and about farmyards and buildings, 

 and in the warm kitchens of farm-houses. But the numbers were found 

 to decrease markedly when isolated houses in the country or manure 

 heaps far from buildings were examined. 



6. In farmyards and manure heaps near buildings in the country 

 such genera as Stomoxys, Seatophaga, Borborus and Limosina pre- 

 dominated. 



7. M. domestica was observed alive in town as late as December 2nd 

 outside and December 9th inside; but one was caught in a house in 

 Grantchester during the last week in December, 1917. Probably those 

 seen in 1916 lingered sometime longer, but these places were not re- 

 visited in that year. 



8. Flies were bred during summer from material used in summer 

 investigations as follows: human faeces — Hydrotaea, Seatophaga, Sar- 

 coyhaga, Muscina sfahidans and small Anlhoingidae; pig manure — 

 Mydaea, Seatophaga, Sarcophaga and small Anthomyidae; cow manure — 

 Morellia hortoum, Erisfalis, Seatophaga, Limosina, Psyeodidae and 

 Borboridae; horse manure — Stomoxys, Borboridae, Limosina, Psychodidae 

 and small Anthomyidae; small carcasses — Hydrotaea and Calliphora. 



For flies bred from larvae and pupae found in various manures during 

 winter see Table I. 



9. Horse manure, which has ceased to ferment and i? cold, has no 

 attraction for the adults of M. domestiea nor nourishment for its larvae, 

 though it still attracts small species such as Limosina, Psychodidae and 

 Borboridae; and though larvae of certain species of fly have been found 

 in it throughout winter. 



10. 99-5 per cent, of the flies bred from horse manure, made in a 

 town stable during 24 hours in the autumn, were M. donieslica, which 

 emerged during 14 days, conimcncing on tlie liHli day. 



11. Male M. domestica, as a wlioh\ started emiMging sooner than the 

 females. 



12. The temperature in a loosely packed heap of horse manure rises 



