parts, and. ground derris root 5 parts; ground derris root 
applied as a powder. This did not adhere well to dry parts of . 
the wound. 
Laboratory tests of larvicides for mature larvae were made. 
A mixture of benzene 95 parts and derris root 5 parts gave 100 
percent control of emergence, whereas benzene alone gave 62 per- 
cent control. Rotenone, pyre thrum extract, and derris resin in 
benzene also gave better control than bezene alone. The follow- 
ing were tried as larvicides in the laboratory: 
Benzene 95 parts, derris root 5 parts. 
Benzene 99 parts, rotenone 1 part. 
Benzene 99 parts, derris resin 1 part. 
Benzene 7^ parts, carbon tetrachloride 25 parts, 
rotenone 1 part. 
Benzene 70 parts, carbon tetrachloride 25 parts, 
derris 5 parts. 
Benzene 7^ parts, carbon tetrachloride 25 parts, 
derris resin 1 part. 
Rotenone and ground derris root markedly increased the toxi- 
city of mixtures of benzene and carbon tetrachloride. Pyrethrum 
extract and derris resin also increased the toxicity of these 
mixtures. 
R. Melvin, in a similar typewritten report in 1935, stated 
that he treated artificially wounded rabbits and guinea pigs in- 
fested with Cochliomyia americana with various chemicals, 5 cc . 
or 1 gm. per treatment. An acetone solution of rotenone (l per- 
cent) killed half the larvae in the wound but a\Lso killed the 
guinea pig. Dry rotenone in 2 tests killed all the larvae in 2 
guinea pigs without affecting the pigs. Pyrocene, a proprietary 
product containing 0.73 percent of rotenone in pine oil with an 
emulsifying agent, proved to be a poor larvicide but a good 
repellent of the larvae. Pyrocene wos tested on 13 guinea pigs 
and 2 rabbits, causing the larvae to leave the wounds, but kill- 
ing only a few. The animals were unaffected by Pyrocene. Of 20 
grown larvae dipped in an acetone solution of rotenone (1 percent) 
19 survivad. In 1935 Melvin stated, in another report to the 
Division, that Pyrocene added to artificially infested wounds 
on guinea pigs caused larvae to leave the wounds and the animal 
was unaffected. Rotenone in acetone (l percent) killed from one- 
third to one-half of the larvae. Rotenone crystals killed all 
the larvae without injuring, the animal. Rotenone in acetone (1 
percent) also killed all eggs dipped momentarily into it. Over 
1,000 eggs less than 3 hours old were used with each test chemical, 
Eagleson reported that the following mixtures containing rotenone 
gave promising results as a fly spray: (A) Rotenone extract, 0.25 
percent; camphor byproduct, 3.3 percent; kerosene, 96 A percent. 
