=- 12 = 
that ethyl alcohol was used as a solvent for several other compounds em— 
ployed in previous experiments without the above recorded effect would 
indicate that the latter explanation will not suffice for this result. 
* * * Tf the use of a solvent for a fumigant lessens the toxicity of that 
fumigant under certain conditions it is very important that those condi- 
tions be known. The results obtained with ethylene chlorohydrin when not 
in solution compared favorably with the effect produced when the ethy- 
lene chlorohydrin was dissolved in water." 
Insecticidal tests of stored pyrethrum powder.--C. F. Stahl, San-— 
ford, Fla., reports that a test was made in which "nearly mature larvae 
of the celery leaf tier (Phlyctaenia rubigalis Guen.) were exposed to 
1/20 gram of pyrethrum dust (that had been stored in open and closed 
containers for different periods of time) for 30 seconds after the dust 
had been blown into a bell jar at 10 pounds' pressure and allowed to 
settle for 2 seconds. This method is an adaptation of that developed 
by the Division of Insect Toxicology and Physiology and has been found to 
give very uniform results. Using 50 larvae in groups of 10 each, the 
results * * * indicate that deterioration of pyrethrum powder is much 
greater in open containers and develops much faster during the second 
year than during the first." 

