282 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



measures in rural districts. In such districts conditions are not so 

 easily controlled by health and other authorities, though very efficient 

 control could be established by means of regulations governing the 

 supply of milk to cities and to^vns requiring the inspection of farms 

 and dairies. Nevertheless, we are faced with the problem of house- 

 fly control under rural conditions and we must examine it. 



The farmer, if he does not store his stable refuse in fly-proof recepta- 

 cles, will probably require a cheap and efficient insecticide. In addi- 

 tion he will usually ask what effect will the application of an insecticide 

 have on the fertilizing of the manure. These are the problems we 

 are called upon to solve and it was with a view to obtaining further 

 data on the comparative value of insecticides in the control of house- 

 flies under rural conditions and the effect of such treatment on the 

 fertilizing properties of the manure that the special investigation which 

 I commenced during the past summer was undertaken. 



A number of investigators have previously carried on experiments 

 along these lines, among whom may be mentioned Howard at Wash- 

 ington, Forbes in Illinois, Herms in California, and Newstead in 

 England, but I feel sure that they would be the first to agree with my 

 contention that the problems, as I have briefly indicated them, are by 

 no means solved and that much more experimental work is required. 

 There are two distinct problems which the study of the comparative 

 value of the insecticides involves, namely, their insecticidal value 

 and their effect on the fertilizing properties of the manure. The latter 

 problem must of necessity be studied largely if not entirely by the 

 agricultural chemist, and as the study of the comparative manurial 

 values has not been undertaken in the course of the past season's work 

 but will be prosecuted, I hope, next year, I shall devote myself to a 

 consideration of the first of these problems. I would impress upon 

 other workers, however, the great desirability of studying the effect 

 of the insecticides on the manure as the farmer requests information 

 on that point. 



In passing, I should not omit to refer to a frequent recommendation 

 which is made to farmers as a means of prevention, namely, that the 

 manure should not be stored in heaps but should be carted away 

 immediately and spread. Where this can be done it is, of course, the 

 simplest method of procedure; apart from that fact it has the additional 

 advantage of being the best policy from the point of view of manurial 

 values. Extensive experiments in Canada and the United States 

 have demonstrated the advantage of spreading the manure over 

 piling it. This, however, is by the way. 



In order to judge the relative values of different insecticides it is 

 necessary to decide upon a means of comparison. In making this 



