-40- 
five to six times as effective as pyrethrins containing pyrethrins 
I and II in ecmal proportions, when mortality counts vrere made 
at the end of 3 days after treatment. No striking synergistic 
effect was produced by 50:50 mixtures of these solutions but they 
appeared to be significantly more effective than had been expected. 
It was doubtful whether the 25 (rotenone): 75 (pyrethrins) mixtures 
^ere more effective than expected. As the results showed that 
mixtures of rotenone and pyrethrins are compatible, attention was 
given to sources of rotenonelike insecticides for mixing with 
pyrethrum extracts for the control of coffee insects in Kenya. A 
few tests were made of acetone extracts of the leaves, roots, and 
stems of a sample of Tephrosia vogelii received from Kenya. The 
effectiveness of these p^rts decreased in the order named. The 
extract of the leaves, "hi ch contain the largest proportion of 
toxic materials, exerted an effect equivalent to a rotenone con- 
tent in the plant material of about 2 percent. The tested sample 
of T. fogelii foliage was, therefore, about one-fifth as effective 
as commercial samples of derris and cube. 
Murphy and V^ndenberg (209) in 1936 compared the action on 
houseflies of sprays containing rotenone, pyrethrins, end Le thane 
384, which contains 50 percent by volume of beta-butoxy-beta' -thic— 
cyanodiethyl-ether. Butyl cellosolve acetate was used to make 
the chemically pure rotenone soluble in petroleum distillate. The 
knockdown by the standard Pec-t-Grady test was determined for 
solutions containing 1, 2, 3, and 4 percent Lethane 384; 1/4, 1/2, 
3/4, and 1 pound of pyrethrum per gallon; and 0.02, 0.05, and 0.1 
percent of rotenone. The results "ere as follows: 
Solution .'Knockdown in 10 Dead in 24 
minutes • hours 
Fercent Fercent 
1 percent Lethane 384 98 35 
Pyrethrum l/4 pound per gallon 69 29 
Pyrethrum 1/2 pound per gallon 85 45 
Pyrethrum 3/4 pound per gallon 89 56 
Pyrethrum 1 pound per gallon 92 67 
Rotenone 0.02 percent 74 47(48 hours) 
Rotenone 0.05 percent 96 56 (do.) 
Rotenone 0.1 percent 98 67 (do.) 
