June, '14] HEWITT: HOUSE-FLY CONTROL WORK 285 



It was not long before experimental results were obtained but these 

 were not of the nature which I had planned to secure. In spite of the 

 fact that the lower edges of the wooden covers had been sunk in trenches 

 and the soil piled round, it was found that some of the larvse tunnelled 

 beneath the cases and pupated in the soil piled outside the case with 

 the result that flies began to emerge outside where provision had to 

 be made for them. In this way a few hundred flies escaped from 

 each of the first two or three experiments, but not sufficient, I think, to 

 materially affect the general results. Accommodation was immed- 

 iately provided for the reception of these wanderers by covering the 

 piled up soil round the outside of the. wooden case with cheese cloth, 

 as shown on plate 9 and the exit at the front led into a wire 

 balloon fly-trap. After this no further trouble was experienced, but 

 the circumstance threw additional light on the pupating habits of the 

 larvse to which I shall refer later ( see Pupation). 



The emerging flies w^ere caught in the wire traps and were counted 

 once or twice daily as circumstances demanded. Heat was used as 

 the means of killing them. I wish to acknowledge my indebtedness 

 to my assistants Mr. Germain Beaulieu, and Mr. Sydney N. Lord who 

 carried out the work of counting the individual flies. 



Experiments 



Six series of experiments, Nos. 11 (1) to 11 (6) were carried out 

 and the following is a summary of the series : 



Exp. No. 11 (1). Untreated. Manure piled August 5th. Covered 

 August 8th on which date second stage larvae were found very num- 

 erous immediately beneath the surface. 



Exp. No. 11 (2). Iron sulphate treatment. Manure piled August 

 5th. Pile sprayed with iron sulphate (2 pounds in 1 gallon of water) 

 on August 8th, on which date many second stage and a few third stage^ 

 larvaj were found in surface layer. Four gallons were applied to the 

 top and sides of heap with a hand spray pump using a coarse nozzle. 

 The vertical sides of the heap made it more difficult to thoroughly 

 drench the manure on the sides. Pile covered August 9. 



Exp. N^o. 11 (3). Chloride of lime; surface treatment. Manure 

 piled August 8th. After piling, 3 pounds of chloride of lime were 

 sprinkled over the top and sides of the heap, the sprinkhng of the 

 vertical sides was difficult and not entirely satisfactory. On August 

 9th living third stage larvae were found within an inch of the surface 



1 As the manure in each case lay in the stable for two or three days before being 

 hauled out and piled in the wire enclosures a certain number of eggs were deposited 

 before hauling, in spite of the stable being screened. But this fact would not vitiate 

 the results of these experiments. 



