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McGovran and Ellisor, in a typewritten report to the 
Division in 1936, stated that the action of chemicals was 
tested in infested articifical rounds on goats. Approxi- 
mately 10 cc. of each larvicide was applied to the infested 
wound and the animal Fas held in such a position that the 
larvicide was in contact with the larvae 2 minutes. A cotton 
plug was inserted in the wounds treated "d. th benzol. The 
other treated and check wounds '-ere left open. The following 
data were obtained from larvicide tests during January and 
February. The materials that killed 100 percent of the larvae 
were as follows: Benzol 65 percent, carbon tetrachloride 25 
percent, ground derris root 10 percent (results of 3 tests); 
benzol 67.5 percent, carbon tetrachloride 25 percent, ground 
derris root 7.5 percent (l test); benzol 70 percent, carbon 
tetrachloride 25 percent, ground derris root 5 percent (ltest); 
clear extract of benzol 70 percent, carbon tetrachloride 25 
percent, ground derris root 5 percent (l test); and clear 
extract of benzol 65 percent, carbon tetrachloride 25 percent, 
ground derris root 10 percent (l test). Mature larvae" were 
dipped for 30 seconds into a mixture of 90 percent of carbon 
tetrachloride and 10 -percent of derris root. The ground derris 
root was allowed to remain in the carbon tetrachloride for 4 
days, then ell the materiel not in solution ^as filtered off. 
This treatment killed two-thirds of the larvae. 
Melvin, in 1936, in a tyne^itten report to the Division, 
described additional laboratory tests on artificially infested 
wounds on guinea nigs in Texas. Pyrocene and mixtures of 
pyrocene and water containing 80, 60, 40, and 20 percent of 
pyrocene not only killed many larvae but also caused larvae to 
leave the wounds. Rotenone crystals killed all the larvae in 
the wounds without affecting the guinea pig. Rotenone (0.5 or 
1,0 nercent) • in General Naval Stores Pine Oil No. 2 was highly 
effective. Pyrocene 60 percent and 80 percent with water 
killed 62 percent and 39 percent, respectively, of larvae dip- 
ped into it. In a similar typewritten report later in that 
yea.r, he said that rotenone ponder killed 100 percent of the 
larvae in rounds. Phenothiazine ^as regarded as the most t>ro- 
mising larvicide for application to wounds. 
The United States Department of Agriculture, Bureau of 
Entomology and Plant Quarantine ( 290 ) , in 1936 reported that 
i ihe '-ork of developing more effective larvicides and repel- 
lents over 200 different chemicals and mixtures r^ere tested* 
Among the many materials tried as larvicides that gave pro- 
mising results was a mixture of benzol and carbon tetrachloride, 
containing 10 percent of ground derris root. In small-scale 
tests ground derris root, rotenone, or derris resins added to 
pine-tar oil anpeared to be more effective as a fly repellent 
than pine- tar oil alone. 
Bushland (47) in 1940 reported that the minimum lethal con- 
centration of rotenone to young larvae wes between 0.05 and 0.08 
