PINK BOLLWORM OF COTTON IN MEXICO. 
9 
As the female does not deposit eggs readily in captivity, diffi- 
culty was experienced in determining exactly how many eggs 
were deposited by a single female. In our experiment usually 
from 5 to 20 moths were confined in one cage. Under these con- 
ditions it was never known which moths had oviposited and 
which had not, and while several hundred eggs were often obtained 
from a cage, it is certain that the maximum number they were 
capable of laying were never obtained. Often heavy, pregnant 
females were found dead in the cage and apparently never had 
deposited any eggs. Upon dissection of gravid females the ovaries 
were found to contain from 75 to 125 well-developed eggs. Busck 
(8) places the number at over a hundred and Willcocks (7) says that 
while small individuals may produce only about 250 eggs, well- 
developed individuals are capable of laying 400 to 500 eggs or more. 
Incubation. 
All of our records were made under laboratory conditions. Figure 
3 shows that the dif- 
ference between the 
maximum and the ,0 ° 
minimum, or the day 
and night tempera- 
tures, for each month 
amounts only to from 
6° to 8° F. 
The egg stage, even 
under these rather 
constant conditions, 
varied from 3 to 12 
days. The range for 
the months of April, 
May, September, and FlG - 3 
October was from 7 
to 12 days, and for June, July, and August it was from 3 to 5 
days, with an average of 4.6 days for the entire season, the average 
being taken from 300 records based on thousands of eggs. 
Hatching . 
The actual hatching of the egg requires only a very short time. 
The young larva can be seen moving inside the shell a short time 
before it actually emerges. An opening is cut in the broad end of 
the egg and the small larva wriggles out and crawls rapidly away 
in search of food. 
The empty shell is white and soon becomes an almost unrecog- 
nizable wrinkled object. It remains on the plant until it decays or 
is carried away by the wind or other agencies. 
11696°-21— Bull. 918 2 
JRN. F£B. MAR. ftPR. mf JUNE JULY M6. SEPT. OCT. NOV. 
Average mean maximum and average mean minimum 
temperatures for 1919 at Ciudad Lerdo, Durango, Mexico. 
