49 
Table XV. — ExperimenU with different strengths of pyrcthrum* 
Totals. 
6 per cent . - 
6 per cent . . 
cenl - 
7 per cent . . 
7 per cent .. 
Totals 
Totals 
Totals. 
Survived. 
Dead. 
"-«*■ 5S 
u* 
4 per cent - 
4 )).-r cent . 
4 per cent . 
44 per cent 
13 per cent 
13 per cent 
13 per « - e 1 1 1 
13 per cent 
13 per cent 
(*) 
25 
') 
32 
4 
11 
40 
8 
- 
19 
<; 
6 
14 
21 
(*) 
•' 
: 
2 ]_' 
12 
. 
24 
19} per cent 
21 per cent 
18 
* Xot counted ; see record of experiment in t<xt. Larva <>f this experiment not included in the totals. 
SUMMARY OF THE EXPERIMENTS. 
When studying the above tabulated results it must be constantly 
borne in mind that the larvae of Boll and Cotton Worms resist the ordi- 
nary liquid insecticides of such strengths as arc usually effective agaiust 
other insects, such as bugs or Leaf-hoppers. Another important fact to 
notice is that whatever effect was obtained from a certain solution or 
decoction is to be attributed solely to it, since the larvae were transferred 
to cages in the shade away from the direct sunlight. The assistance 
of direct sunlight in producing scorching effects with the oil emulsions 
is entirely eliminated, and explains why the larvae seem to have with- 
stood unusually strong solutions. For this reason the results obtained, 
though possibly less striking, have greater significance as to the real 
value as insecticides of the combinations made. 
The foliage in the field was injured less than might be expected with 
such strong solutions on account of the cool, dewy nights and moderate 
temperatures during the day at the time when the experiments were 
made. It is needless to dwell further upon these conditions, except to 
state thai the same strengths of emulsions if applied during the heat of 
day in midsummer would affect both larva- and foliage proportionately 
in a more decided and vigorous manner. This, however, has no direct 
bearing upon the primary purpose of the experiments, which was to 
1 1935— No. 29 4 
