5 
Seldom is the stalk damaged above the third joint from the ground, 
although the larvee, when small, are found in the large midribs of 
the lower leaves and later in the season, when the food supply is 
restricted, even in succulent nubbins farther up. They sometimes 
also penetrate the underground part of the stalk in feeding and enter 
some of the larger brace roots for a short distance. 
The larve of the second generation work in a similar manner, except 
that at the time they appear the tassel has been formed; hence the 
damage is now confined altogether to the lower stalk. Thus, instead 
of arranging to pass the pupal stage in the upper stalk, they pene- 
trate to the root to hiber- 
nate and there, as larve, 
pass the winter in a qui- 
escent state (fig. 3). 
SEASONAL HISTORY. 
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During the winter this 
enemy of corn is to be 
found as a robust, creamy- 
white larva of the second 
generation in the lower 
part of the stalk—or of 
the stubble, if, as is usu- 
ally the case, the corn Cc 
has been cut. In this lo- Fic. 4.—The larger corn stalk-borer: a, Female 
eation the larva forms a moth; b, wings of male; ¢, pupa. All somewhat 
emialiscayity below the sur- “"*7#*t " (Oxleinal.) 
face of the ground, well protected from birds, predaceous insects, 
and unfavorable weather conditions. From the time the corn is 
mature in the fall until about corn-planting time in the spring this 
caterpillar remains inactive. About the time the ground is being 
- prepared for corn, from March 15 to April 30, depending on the 
locality, this larva changes into a reddish-brown pupa or chrysalis 
(fig. 4,¢). After a further period of ten or more days’ inactivity the 
adult insect emerges from the pupa case as a pale brownish-yellow 
moth (fig. 4, a, 6) ,with a spread of wings of about an inch and a quarter. 
The moths then mate and the females begin at once to deposit eggs 
on the underside of the leaves, the larve hatching from these eggs 
forming the first generation. 
The eggs hatch in from seven to ten days and the young larvee 
begin their destructive work in the upper leafy portion of the plant, 
later descending to the base of the stalk, where they attain full 
growth. This period, from egg to full-grown larva, requires from 
twenty to thirty days, depending largely on the weather conditions 
[Cir. 116] 
