-3b- 
sample of derris was more effective as a housefly snray then a 
similar keorsene extract of a good sample of pyrethrum. Pyrethrum 
was speedier in its initial action. Theoretically, mixtures of 
derris and pyrethrum extracts should combine the advantages of 
both. The same authors reported later in the year that only 1 of 
9 samples of Tephrosia native to the United States (T_. latidens 
from 'Florida) had sho^n any promise when tested as a kerosene 
extract against houseflies. It was not so effective as a sample 
of derris. 
Campbell, Sullivan, and Smith (55) in 1933 determined the 
relative toxicity of nicotine, anabasine, and other alkaloids, 
and of rotenone for control of houseflies. Rotenone, 0.1 gm. per 
liter of absolute ethyl alcohol, sprayed on flies in a screen- 
covered petri dish at the bottom of a cylindrical e-lass spraying 
chamber, usually killed mere than 50 percent of the flies. None 
of the alkaloids affected them. 
G-stirner and Hunerbein ( 127 ) in 1933 tested samples of bar— 
basco root and bark, thought to be Tephrosia piscatoria , against 
houseflies. With the ether extract of the root, a significant 
insecticidal effect was obtained, but this ^s very much less 
than the effect of pyrethrum flowers. The bark had no toxic 
effect against houseflies. 
H. H. Richardson ( 239 ) in 1933 tested kerosene extract^ of 
derris, both alone and mixed with kerosene extracts of pyrethrum, 
against flies. Kerosene extracts of derris powder (2,9 percent 
rotenone)' were prepared, by first macerating the powder for several 
hours with kerosene in a glass percolator and then allowing per- 
colation to proceed slowly. Extracts were prepared on the basis 
of 23.8 gm. of powder to 100 cc. of kerosene (approximately 2 lb. 
to 1 gal.). Pyrethrum extracts were prepared by the same method 
in the proportion of 11.9 gm. of pyrethrum powder (0.26 percent 
pyrethrin I) to 100 cc. of kerosene (approximately 1 lb. to 1 
gal.). The combination of derris extract with pyrethrin extract 
was prepared by r.dding 16.6 cc. of the derris extract, orepr-red 
as above, to 83.3 cc. of the pyrethrum extract. This was tested 
in comparison with another sanvole of the same' pyrethrum extract, 
diluted with 16.6 cc. of kerosene to 83.3 cc. of the extract. 
The results of the insecticidal tests were as follows: 
Test solution | 
Tests 
Plies- 
Average t 
ime' 
l& rtality 
reouired 
to 
after 24 
1 
paralyze 
hours 
Number 
Number 
Seconds 
F ercent 
Kerosene 
2 
94 
405 
18 
Kerosene extract of 
derris 
2 
110 
58 
Extract of pyrethrum 
4 
197 
197 
46 
Extract of nyro thrum nlus 
derris extract 4 
198 
190 
59 
