MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 3 
much foliage had been consumed. In other cases, where the entire 
leaf except the midrib and larger veins was consumed, the measure- 
ment was obtained by measuring an average-sized leaf and substi- 
tuting it for the leaf which had been destroyed. Careful attention 
was given to the condition of the foliage throughout the experiments 
so as to supply the larvae with palatable food at all times. 
Experiment I. 
COMPARISON" OF THE KILLING EFFECT OF DOUBTFUL STOMACH POISON'S WITH VARIOUS 
ARSENICALS ON LARVJ3 OF THE FALL WEBWORM. 
In this experiment the arsenite of zinc compounds and other pro- 
prietary insecticides were used at the strengths recommended by the 
manufacturers. The homemade arsenical compounds, where sodium 
arsenate was employed, were used at a rate to equal 0.8 pound 
sodium-arsenate content to 50 gallons of water, except in the case of 
arsenate of .iron, which was used double strength. Arsenite of lime, 
homemade, was used at the rate of 2 pints to 50 gallons of water. 
All other compounds containing arsenic were used at a strength 
equivalent to 2 pounds of arsenate of lead paste to 50 gallons of water. 
These calculations were based upon a 15 percent arsenic-oxid (As 2 5 ) 
content in arsenate of lead paste. Compounds containing no arsenic 
were used at the rate of 6 pounds to 50 gallons of water. The larva? 
used in this test were about 4 days old. The results are given in 
Table I. 
