EXPERIMENTS WITH KEROSENE ON THE COTTON WOBM. 43 
The A' and B' were not stable longer than two days: the remaining 
dilutions barely one day. 
With the exception of the zamia emulsion, all others were better to 
use the day of manufacture. 
A mixture called murvite was sent me for trial. It gave similar re- 
sults to the milk emulsions, when diluted in a corresponding manner. 
Effects upon the cotton plant. — These varied greatly, owing to the 
weather subsequent to the application. 
Emulsions A and B, A 7 , B', 1^ to 2 per cent, kerosene, did not harm 
the cotton plant if two cloudy or showery days followed their use. A 
bright sunny day scorched the tips and edges of the tender leaves badly. 
Emulsions C, D, and E, C, D', £', produced no bad results upon leaves 
or bolls, and were repeatedly tried, with uniform effect-. 
Effects upon larva?. — 1. 1 colonized five hundred full-grown larvae upon 
five cotton plants, and sprayed them with emulsion A, soap series. In 
five minutes forty larv;e dropped off' the plants, trembled, and soon died; 
in an hour but one hundred remained, none feeding, all hanging from 
the stems and leaves : in three hours but eight survived ; the next day 
all were dead, and the cotton leaves badly withered. 
2. I prepared forty gallons of solution B 7 , milk, and sprinkled thor- 
oughly one-fourth acre of cotton. The stalks average seven feet in 
height, and the worms were very plentiful. 
The next day apparently but one in each hundred were living; the 
day following that the difference was quite marked, and at this time, 
three weeks afterward, the surrounding cotton is defoliated, the sprinkled 
section remaining vigorous and green. 
3. I colonized one hundred larvae, all ages, on a cotton plant ; spr i 
these with solution C, milk: fifteen worms fell off in twenty minutes: 
the remainder quit feeding. The next morning but two remained, feebly 
alive. 
4. One hundred large larvae were colonized and sprayed with solution 
D', milk. Id ten minutes ten dropped oft"; in half an hour but thirty, 
five showed vitality: in four hours all were dead. 
5. One hundred larva-, small size, were sprayed with the one percent 
kerosene-zamia emulsion ; all died within an hour. 
6. One hundred small larvae sprayed with emulsion B, soap, died in 
one hour. 
7. Three hundred large larva- were sprayed with solution C . milk. 
The next day but twelve showed signs of life, and they were evidently 
moribund. 
8. Three hundred large larvae were sprayed with the zamia emul- 
sion : all died within four hours, and the repetition of experiment l with 
this solution gave better results than with milk or soap emulsions, the 
zamia perhaps contributing some toxic action. 
I repeated these experiments with all the emulsions till satisfied that 
