-35- 
percent when tested on house flies by the Peet-Gredy method. 
Rotenone at the same concentre tion gave "an average knock-down 
of 76 percent and en average kill of 30 percent. A mixture 
of 31.7 mg. of pyrethrins with 31.7 mg. of rotenone gave an 
average knock-down of B5 percent and an average kill of 42 per- 
cent. Because of the lo 1 " solubility of rotenone in the oil, 5 
percent of acetone was added to the solution. Allowance ^as 
also made f or • the petroleum ether introduced when the stock 
solution of pyrethrins was diluted with the mineral oil. All 
the solutions tested, therefore, contained 5 percent of acetone 
and 7.2 percent of petroleum ether, by volume. Neither acetone 
nor p etroleum ether was toxic to flies in these concentrations. 
The mineral oil gave a kill of less than 6 percent by the Peet- 
Grady method. The authors concluded that the addition of small 
amounts of rotennne to oil solutions of -oyrethrins does not 
increase the toxicity as much as does the addition of the same 
amount of pyrethrins. 
The United States Department o^ Agriculture, Bureau of 
Entomology (287), in 1932 'reported that tests of alcoholic 
solutions of rotenone and 13 derivatives of it against houseflies 
showed that rotenone was more toxic than these derivatives, that 
dihydrorotenone was nearly as toxic as rotenone, followed bv 
rotennne hydrochloride and acetyl rotenone, and that the other 
10 derivatives were relatively nontoxic. Tests against the house- 
fly of dusts of derris root and of rotenone 'showed that this 
species is killed by extremely small quantities of both. Com- 
parative tests of powdered derris root and of the same root from 
,r hich rotenone had been extracted showed that thoroughly extracted 
root was not toxic to houseflies. Comparative 'tests of alcoholic 
solutions of the pyrethrins and rotenone showed that the former 
has a more rapid effect on houseflies, but that the insecticide.l 
value of the latter is greater. Rotenone when sprayed in alcoholic 
solution on houseflies acted as a contact poison. It had no effect 
on flies when administered in suspension by mouth, nor did it have 
any effect in the vapor phase at room temperature. 
B=dertscher (10 ) in 1933 reported the results of fly tests 
--'ith solutions containing both nyrethrum extract and rotenone. 
Samples representing four brands of commercial fly sprays were 
diluted "'ith an eoual volume of a base solvent (Deoba.se) contain- 
ing 0.1 percent of rotenone. These mixtures ^ere compered bv the 
Peet-Grady method with the original samples and also "ith the 
original samples diluted with an eoual volume of base solvent. 
In all cases the addition of rotenor.e increased the killing po^er 
of the sprays to flies. Badertscher concluded that 0.05 percent 
of rotenone in a housefly spray has value, but that the intelligent 
use of rotenone in this field reouires a knowledge of the amount 
of active principles of pyretbrum ^*ith ^hich it is to be incorporated. 
Cam-obeli and Sullivan (51, 52) in 1933 reported the results 
of 13 series of tests, shoeing that e kerosene extract of a good 
