466 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



In experiments 13 and 14 the results that were obtained seem to 

 approach the incredulous. The high percentages attained in de- 

 stroying the eggs is substantiated by the figures that were obtained 

 in counting the fruit for roller injury. In number 13, 99.3 per cent of 

 the eggs were killed and in number 14, out of 1,006 eggs examined, 

 only four hatched. This give a killing percentage of 99.6 per cent. 

 The fruit loss in this last experiment amounted to .8 per cent, eight 

 injured apples being found in examining 1,000. 



In summing up the experimental results it is found that efficiency 

 is approached in experiment 5 where lead arsenate is used at the rate 

 of 6 pounds to the 50 gallons of water and obtained in experiments 

 11 to 14 inclusive where miscible oil was used. In comparing the 

 costs attached to using these materials, the miscible oil must be con- 

 sidered by far the more economical. The lead application costs for 

 materials alone in the neighborhood of $1.65 per tank of 200 gallons. 

 The miscible oil, as used in experiment 12, will cost about $1.50 per 

 tank and, as it cannot be used in combination, the application will 

 be extra. The marked increase in efficiency attained with the oil, 

 however, more than warrants its use. For complete safety to the 

 foliage, the oil applications should be made before the buds burst. 

 Apparently no permanent injury occurred in our experimental plats 

 this season from the late applications, but the margin of safety is 

 extremely small and such a proceedure should not be generally fol- 

 lowed. 



The author wishes to thank Mr. F. W. Radford and Mr. Frank 

 Davidson for their generous assistance and cooperation which has 

 made possible the conducting of the large series of experiments during 

 the past season. 



Vice-President Cooley: Mr. F. C. Bishopp will present the 

 next paper. 



A PRELIMINARY STATEMENT REGARDING WOOL MAGGOTS 

 OF SHEEP IN THE UNITED STATES 



By F. C. Bishopp and E. W. Laake, of the Bureau of Entomology ^ 



Introductory 



The wool maggots, although pests of importance to sheep raisers, 

 have received practically no attention from investigators in the United 

 States. In Europe, especially in the British Isles, the wool maggot is 

 one of the most serious insect pests of sheep. In Scotland, in partic- 



1 Published by permission of the Chief of the Bureau of Entomology. 



