E. R. Spbybr 135 



Experiment 11. Control with grape juice. 



Date:— September 8th-10th. 



General weather conditions: — Cool, some rain. 



Duration of experiment: — 48 hours. 



Flies caught 



The average for each pair of traps (A, A'; B, B'; C, C) is, then, about 

 70 flies for the 48 hours. Traps B and A' are seen to be in the most 

 favourable positions, and the pairs A, A' and B, B' are credited with the 

 highest number. By interposition the differences are eliminated in the 

 following experiments. 



It might be thought that many of the sweet-smelling essential oils 

 are attractive to the house-fly, but this is here shown to be a mis- 

 conception, for many of them are, to a certain degree, actually repellent. 



Experiment 12. 



Date: — September 15th-18th. 



General weather conditions: — Warm, bright. 



Duration of experiment: — 76 hours. 



Flies caught 



Substance Amount ,, -» N 



c.c. <J ? Total 



Cedar oil 20 



Oil of juniper berries 20 1 1 



Oil of Pinus Sylvestris 20 



At the same time, three traps were placed in the stable used for the 

 experiments in Section I for 26 hours. The figures were exactly similar 

 to the above, and in both cases the female fly in the juniper oil trap was 

 dead. It is probable that the two flies entered by accident. 



Experiment 13. 



Date : — September 1 8th-2 1 st. 



General weather conditions : — Warm, bright. 



Duration of experiment: — 46 hours. 



Flies caught 



