34 BULLETIN 746, U. S. DEPARTMENT OP AGRICULTURE. 
One adult emerged in December from eggs laid as late as Septem- 
ber 25, although the others from this mass of eggs hibernated. In 
general, it seems that .most of the larva? from eggs laid after the 
middle of September hibernate if they are not killed in the mill, but 
this depends somewhat on the season, as more will develop in a late 
fall. All instars of the larvae hibernate. Small first and second 
instar larvae have been seen as late as the middle of December crawl- 
ing over the cane tops, and these would hibernate if they found suit- 
able places. Hibernation is not what may be called complete, since 
the larvae remain active on warm days and continue to feed to some 
extent. When infested cane is windrowed in the fall it is often 
badly damaged by the borers continuing their feeding throughout 
the winter, destroying many eyes and tunneling the stalks until they 
become brittle and break with handling. The well-grown larvae con- 
tinue molting at irregular intervals throughout the winter, but do not 
increase in size ; in fact, they are even smaller and more flabby in the 
spring than they are in the fall. The small larvae increase slowly in 
size and all hibernated larvae are of a very uniform size in the spring. 
PLACES OF HIBEENATION. 
The larvae hibernate in scraps of cane, tops of the cane plant, 
stalks of large grass, cane stubble, and planted and windrowed cane. 
Very few are to be found in stubble and grass stalks, however. No 
larvae have been found in cornstalks during the winter, for these dry 
out and become unattractive to the moth borer long before cold 
weather begins. The usual place of hibernation of the closely re- 
lated species D. zeacolella, however, is in the taproots of corn. 
The favorite places of hibernation are scraps of cane left after 
grinding, and windrowed and planted cane. The windrow forms 
an ideal place for hibernation, the larvae being well protected by the 
earth and the quantity of leaves covering the stalks. 
EMERGENCE FROM HIBERNATION. 
The hibernating larvae pupate in the spring and emerge as moths 
when the cane is from a few inches to a foot or more in height. 
Though planted cane is covered with earth, this is often washed away 
by a heavy rain, exposing or partially exposing the seed cane. Moths 
have been found to emerge from cane under one-half inch of packed 
soil so that it is often possible for them to emerge from planted cane. 
There is of course no obstacle to their emergence from grass or cane 
stubble. 
The times of emergence from planted cane under observation were 
May 7, May 21, and June 1, 1914, and the earliest emergence in the 
insectary was on May 8. A first-instar larva, however, was collected 
in the field as early as May 5, indicating that the parent moth must 
have emerged during the last few days of April. 
