LARGER CORN STALK-BORER. 5 
SEASONAL HISTORY. 
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 usually the case, the corn has 
been cut. In this location the larva forms a small cavity below 
the surface of the ground, well protected from birds, predaceous 
insects, and unfavorable weather conditions. From the time the cornu 
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, c). After a further period of 10 or more days’ inactivity the 
adult insect emerges from 
the pupa case as a pale 
brownish-yellow moth (fig. 
4, a), with a spread of 
wings of about an inch and a 
fourth. The moths then ; ; Ske 
mate, and the females begin Ly, We aease 
at once to deposit eggs on ie a 
the underside of the leaves, 
the larve hatching from 
these eggs forming the first 
generation. 
The eggs hatch in from 7 
to 10 days and the young 
larvee begin their destructive 
work in the upper leafy 
portion of the plant, later ia. 4.—The larger corn stalk-borer: a, Female moth; 8, 
descending to the base of the ante oe All somewhat enlarged. (Au- 
stalk, where they attain full 
growth. This period, from egg to full-grown larva, requires from 20 to 
30 days, depending largely on the weather conditions and the vigor of 
the plant. The larvee when full grown pupate in the stalk, usually 
in the second or third joint from the ground, and in from 7 to 10 
days the adult moths of the first generation emerge. 
The eggs for the second generation are laid in similar positions 
on the lower leaves or on the stem, and the larve, after feeding for 
a short time on the leaves, go directly to work in the stalk, completing 
their larval growth in the pith of the lower stalk as did the larve 
of the first generation. No damage is done to the upper part of the 
plant by larve of the second generation. 
By the time the larve of the second generaticn are full grown 
the corn is rapidly nearing maturity, and, instead of pupating in 
