INSECTS INJURIOUS TO CORN 



173 



moth is a brownish-yellow color with wings expanding 1| inches, 

 the hind-wings being darker and bearing faint markings (Fig. 128). 

 The eggs are laid at dusk upon the under surface of the leaves of 

 the young corn, and hatch 

 in from seven to ten days. 

 The eggs are flat, scale- 

 like, and placed in rows 

 of from two to twenty- 

 five, slightly overlapping 

 each other. They arc 

 3 /ioo inch long, by two 

 thirds as wide, at first a 

 creamy-white, but grad- 

 ually becoming a reddish^ 

 brown. The young larva 

 bores into the stalk, often 

 destroying the " bud," 

 and then at or near the 

 ground, where it burrows 

 upward in the pith, 

 seldom damaging the 

 stalk above the third 

 joint. As the borers 

 grow they become quite 

 active and frequently 

 leave and re-enter the 

 stalk, thus making sev- 

 eral holes. The caterpil- 

 lars become full grown 

 in twenty to thirty 

 days, and are about one inch long, dirty-white, thickly covered 

 with dark spots, each of which bears a short, dark bristle. 

 The mature caterpillar bores outward to the surface of the stalk, 

 making a hole for the escape of the adult moth, which it covers 

 with silk, and then transforms to a pupa in its burrow. This 

 occurs during July, and the moths of the second generation emerge 



FIG. 126. Work of the larger corn stalk-borer: 

 a, general appearance of stalk infested by 

 the early generation of borers; 6, same 

 cut open to show pupa and larval burrow. 

 (After Howard, U. S. Dept. Agr.) 



