30 
BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
such infestation is disclosed. When once inside the ear, the larvae 
may tunnel through all parts of the grain and the cob, partially or 
totally destroying the kernels of grain which they attack. (Fig. 12.) 
The character of the actual feeding in the grain is subject to wide 
variation; it may consist of long irregular surface tunnels between 
the rows of the kernels, or it may consist of tunnels just underneath 
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lilt 1 1 
EH i ! 
Fig. 
11. — External view of ear, showing extruded frass and numerous punctures 
caused by larvae of the European corn borer 
the upper surface of the kernels, or again large irregular areas may 
be fed upon with no apparent regularity of procedure. Tunnels in 
the cob may extend either longitudinally or transversely through it 
(fig. 13), and when injury of this type occurs early in the develop- 
ment of the ear, it may seriously interfere with the normal formation 
of the grain. Where several borers are thus feeding upon the grain 
and the cob, the resulting damage usually is very severe, but when 
only one or two borers occur within the ear, the damage to the 
