PINK BOLLWORM OF COTTON IN MEXICO. 
45 
are pink with crawling larvae. Many of the double seeds are torn 
apart in the cleaner and gin, though some go through unharmed. 
It is extremely disappointing to look for larvae in seed which comes 
from heavily infested cotton. In such seed in the winter or spring 
one can rarely collect more than 75 to 100 live larvae in the course of 
an eight-hour day. Ten samples of 2,500 seeds each were taken on 
different occasions during February and March, 1918 and 1919, 
from seed houses, examined seed by seed, and only 9 live larvae were 
found. 
For our rearing work larvae were removed by hand from the bolls 
and placed in fruit jars with seed to pass the winter. Table XXII 
shows that the mortality among larvae removed from bolls in No- 
vember and stored in the laboratory during the winter of 1918 and 
1919 was 22.6 per cent and that 0.4 per cent were still alive November 
20, 1919, when the work was discontinued. 
Other larvae were disturbed as little as possible and were left in 
the double seed where they had prepared to spend the winter. The 
double seed were picked from the lint by hand and stored in the 
laboratory under the same conditions as the others. Table XXIII 
shows that there was 16.2 per cent mortality among larvae in double 
seed and that 4.4 per cent were still alive on November 20, 1919. 
Table XXII. — Mortality among larvse removed from bolls and kept in the laboratory in a 
condition as near to that of stored seed as possible. 
Date collected. 
Number 
entering 
resting 
stage. 
Number 
emerged. 
Per cent 
mortality. 
Per cent 
emerged. 
Number 
alive Nov. 
20, 1919. 
1918. 
Sept. 30 
83 
281 
256 
269 
260 
282 
309 
239 
320 
299 
277 
260 
244 
265 
125 
71 
191 
180 
153 
183 
220 
255 
201 
255 
244 
211 
193 
192 
242 
99 
13.2 
31.6 
28.9 
43.1 
29.7 
22.0 
17.5 
15.4 
19.6 
17.7 
23.4 
25.0 
20.9 
8.6 
20.8 
85.5 
68.0 
70.3 
56.9 
70.3 
78.0 
82.5 
84.1 
79.6 
81.6 
76.2 
74.2 
77.7 
91.3 
79.2 
2 
2 
2 




1 
2 
2 
1 
2 
I 
1 

Nov. 13 
Do... 
Do 
Nov. 14 
Nov. 15 
Do 
Do 
Do... 
Do 
Do... 
Nov. 16 
Do 
Nov. 17 
Nov. 19 
Total 
3,769 
2,890 
16 
0. 4 per cent; 
22.6 
77.0 
The moths were removed daily and a record kept for each jar. 
The percentages used are based on the number- of moths emerging 
and the number of dead and live larvae found in the jar at the end 
of the experiment. As these larvae were carefully removed by 
hand and stored indoors, the mortality was the minimum that can 
be expected and is much lower than in seed ginned and handled 
on a commercial scale. It is difficult to determine the mortality 
