18 BULLETIN 918, U. S. DEPARTMENT OF AGRICULTURE. 
Table VII. — The monthly emergence of moths from resting larvae for 1918 and 1919. 
Months. 
Number of 
moths 
emerged. 
Per cent of 
total emer- 
gence. 
Number of 
moths 
emerged. 
Per cent of 
total emer- 
gence dur- 
ing period, 
covered. 
March 
April 
May 
June 
July 
August 
September . 
October 
November. 
3S1 
236 
525 
355 
105 
23.5 
14.6 
32.5 
21.9 
6.5 
1.0 
1 
125 
851 
1,811 
2,302 
708 
84 
40 
8 
Total. 
1,618 
100.0 
5,930 
C 1 ) 
2.1 
14.3 
30.6 
38.8 
12.0 
1.4 
1 No complete record. 
Moths emerging in 1918 were from larvse collected in seed in 
February, 1918; those emerging in 1919 were from larvae collected 
in bolls during November, 1918. Complete records are not available 
for December, 1918, or January, February, and March, 1919, due 
to absence from the laboratory. The percentages of moths emerging 
each month are based on the total number of moths which emerged 
and not upon the total number of larvse. Of the larvae collected in 
November, 1918, 4.4 per cent were still alive and had not pupated 
on November 20, 1919, when the records were discontinued. 
A study of Table VII shows that emergence took place much earlier 
in 1918 than in 1919. During March, 1918, 23.5 per cent of the 
moths emerged and the maximum of 32.5 per cent was reached in 
May, while in 1919 only 2.1 per cent emerged in April and the maxi- 
mum of 38.8 per cent was not reached till July. This seasonal 
variation depends largely upon the temperature and humidity. 
The winter of 1917-18 was unusually mild and there was an excep- 
tionally hot period during the first week of March which hastened 
pupation. It was also found that dampening the seed or lint hast- 
ened emergence and a rain followed by warm weather in March 
or April would no doubt cause large numbers to emerge. As a rule, 
moths emerging before the first of May would find no suitable places 
for oviposition and would not be a factor in starting the infestation 
in the following crop. 
ISSUANCE OF MOTH. 
The issuance of the moth from the pupal skin requires a very 
short time. The pupal skin breaks or splits along the dorsal side 
and the math works its way out and crawls upon some object in the 
open so that the wings may develop normally. As soon as the 
wings have extended to their full length they are raised and held 
in a vertical position from 5 to 15 minutes to become perfectly 
