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three others made slight movements of the legs, the remainder being 

 dead. In all these plots there were many dead bugs on the ground 

 where the wheat had been sprayed. The same was true of other ex- 

 periments made in the same way, in which none of the bugs were sep- 

 arated for counting. 



In another lot of fifteen experiments with Black Leaf 40, chinch- 

 bugs collected in hibernation were placed on dry cloths in lots of 

 twenty, sprayed with tobacco solution, and transferred at once to dry 

 cardboard boxes. Examined from twenty-four to forty-eight hours 

 afterwards 71 percent of the bugs so handled were found to be dead. 



Additional experiments of the same general description, made 

 with kerosene emulsion containing 5 and 10 percent of kerosene, ap- 

 plied to chinch-bugs in the wheat, showed that this insecticide was 

 practically without effect under these conditions. In three such ex- 

 periments only three bugs were killed. That this was due in part to 

 the conditions in the field is shown by the different result of tests made 

 by spraying kerosene emulsion upon chinch-bugs placed on a dry cloth 

 and transferring them to cardboard boxes. In this case 54 percent of 

 the bugs were killed as an average of eight experiments. Similar 

 trials were made of scalecide at various strengths, from 1 percent to 

 10 percent in water, with practically no effect on the bugs. Emulsions 

 of gasoline and soap containing 5 and 10 percent of gasoline proved 

 similarly useless, as did also solutions of iron sulphate in proportions 

 of one pound and two pounds to the gallon of water. 



As the tobacco extracts prepared by manufacturing companies are 

 rather expensive, it was thought possible that cheaper and equally 

 effective sprays might be made direct from the wastes of tobacco fac- 

 tories, and a few tests of this supposition were also made in 1911. 



In the best of these three ounces of cigar clippings were boiled in a 

 gallon of water for half an hour and diluted with twice as much water 

 in which an ounce of soap to the gallon had been dissolved by boiling. 

 This mixture was applied to infested corn with a portable automatic 

 sprayer which discharged a small straight stream. The result as 

 tested by a careful examination of the sprayed hills of corn twenty- 

 four hours later showed that from 21 to 48 percent of the bugs had 

 been killed. 



Experiments with Solutions of Soap. — In all these mixtures thus 

 far described, whether made with kerosene or tobacco, small amounts 

 of soap were used either to produce an emulsion or to increase the 

 spreading and penetrating power of the tobacco solution. To distin- 

 guish the insecticide properties of these ingredients experiments were 

 made with soap solutions alone, with results so unexpectedly favorable 

 that an elaborate series of tests were made at Springfield during the 

 winter of 1912-13 with a large number of different brands of soap ob- 

 tainable on the ordinary market. In each of these experiments a 

 number of chinch-bugs collected from their hibernating quarters and 



