448 The Manure Heap and the House-Flij 



Eristalis tenax L. ... ... I 



Musca domestica L. ... 3 



Sto)i>oxi/.s cnlcitidns L. ... 5 



Faniiia caniculuris L. ... 1 



Chortofhila cilicrura Rdi. ... 4 



Hydro! nea armipes V. ... 2 



The result does not support the behef that any of the flies taken 

 were breeding to an appreciable extent in the material used. The 

 manure had ample opportunity of becoming infected either at the army 

 stable or at the laboratory. During this period ,1/. domestica was not 

 by any means commonly observed in the neighbourhood. 



Experiment II. As a control and in order to discover whether 

 there was anything in the experimental method which might inhibit 

 the growth and development of the larvae, a quantity of horse manure 

 was obtained from a stable closely surrounded by houses and adjacent 

 to a bakery. This material was treated precisely as in Experiment I, 

 except that it was all put on the heap at once and immediately covered 

 in. This was done on July 3()th. By August 12th flies had practically 

 ceased to hatch out, and during the thirteen days the following were 

 trapped from the heap : 



Musca domestica L. ... ... 798 



Slomoxys cnlritrans L. ... ... 31 



Chortopliila cilicrura Rdi. ... 22 



Fannia canicularis L. ... ... 4 



Hydrotaea armipes F. ... ... 10 



This experiment showed in a marked degree the effect of such 

 attractive adjuncts as a bakery and numerous houses in close proximity 

 to the manure bin. The flies did not hatch in great numbers from the 

 trenches, the proportion of ,1/. domestica being : 



Direct from heap ... ... 682 



From trenches ... ... 116 



which gives a proportion of over 85 per cent, hatched direct from 

 heap. The highest temperature recorded for this heap was about 

 50°. This dift'erence in temperature does not however accoimt for the 

 difference in the number of the flies, as careful examination of Heap 1, 

 before it was covered in, showed that it was not really infected, whilst 

 the larvae could easily be seen in Heap 2. 



