DERRIS AS A PARACITICIDE 49 
Conclusions 
From the experiments undertaken it is evident that derris furnishes 
a very efficient insecticide, particularly when used as a powder against 
ecto-parasites. It is effective, easily applied, not repugnant to the 
animal or man, and retains its insecticidal properties unaltered in ihe 
open air. It should be used about the same as pyrethrum powder, and 
in the 20% derris-80% tobacco dust mixture affords a killing powder 
about as great as commercial pyrethrum. Its stability in insecticidal 
power recommends it above pyrethrum even at a slightly higher price. 
It seems, however, to lack the instantaneous effect of the latter, and is 
not effective against flies when blown into the air. As a check against 
roaches, ants, and insect ecto-parasites, it is fully the equal of pyrethrum 
as ordinarily purchased. 
The powder is not now obtainable commercially. When finally 
placed on the market it will probably cost about the same as pyrethrum, 
possibly a little less, and should make a very desirable addition to the 
means of combating household insects and external animal parasites. 
Bibliography 
McIndoo, Sievers, and Abbot, 1919—Derris as an Insecticide. Jour. Agric. Re- 
search. Wash., D.C.; 17; No. 5, pp. 177-200. 
Mathieu, E., 1920—Tuba Root (Derris eliptica) as an Insecticide. The Gardens 
Bull. Straits Settlement, Singapore; 2; No. 6, pp. 192-197. 
Van Hall, C. J. J., 1920—Derris als Insecticide. Teysmannia, Batavia; 31; No. 4, 
pp. 159-166. 
