THE SUGAR-CANE MOTH BORER. 
21 
of the egg stage at the prevailing temperatures during the different 
months is shown in Table III and is graphically illustrated in fig- 
ure 6. 
Table III. — Relationship of mean temperature to the developmental period 
of the sugar-cane moth borer in the egg stage. 
Period. 
Average 
mean tem- 
perature. 
Number of 
records. 
Period. 
Average 
mean tem- 
perature. 
Number of 
records. 
Days. 
4 
5 
6 
o p 
82.8 
81.7 
78.9 
10 
41 
7 
Days. 
7 
8 
9 
o p 
75.2 
72.1 
72.4 
1 
1 
1 
DEVELOPMENT. 
When the eggs are first deposited they are creamy white, and in a 
field of cane are practically invisible against the light green of the 
cane leaves. They gradually darken until they are reddish brown, 
with the eyes of the embryo showing through as two small black 
spots. Later the head turns black and the eyes can not be distin- 
guished, but the segments of the larva are discernible. The head 
seems to fill the whole egg cavity and gives to the egg mass a bluish- 
black cast. Just before hatching the larva can be seen moving 
within the eggshell. 
HATCHING. 
Hatching usually occurs in the early morning during the summer, 
and later in the day in cooler weather. Observations indicate that all 
eggs in a given cluster hatch within a few hours. The larva emerges 
from the egg by rupturing the upper surface, leaving it torn and 
ragged but without altering the arrangement or position of the egg 
in the cluster. The empty eggshells are papery and almost trans- 
parent, but they show a slight marking under the microscope. The 
cluster of eggshells adheres to the leaves for some time before being 
washed away by rains, and is more conspicuous at this period than 
it is before hatching. 
While no definite record has been maintained of the percentage 
of eggs which hatch, it is only occasionally that one or two in a clus- 
ter from a fertilized female fail to produce larvae. Eggs from 
unfertilized females do not hatch. 
LARVA. 
FOOD HABITS. 
The larvse are active from the time of hatching and almost imme- 
diately begin their search for food. Those from a single group of 
eggs congregate in the terminal buds of two or three plants in the 
immediate vicinity of the place where hatched and begin feeding 
