26 
BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
After gaining entrance to the stalk the borer tunnels either upward 
or downward, usually the former, according to its individual pref- 
erence. The character of this tunnel is subject to considerable varia- 
tion, but usually the borer follows nearly a straight course for several 
inches through the pith and generally lengthwise of the plant. The 
tunnels of 41 individual borers were found to average 8.6 inches in 
Fig. 
-Broken corn tassel, showim 
injury caused by larvae of the European corn 
borer 
length. (See Table 14.) The tunnels made by fully grown larvae, 
when tunneling in green and succulent cornstalks, average 0.19 inch 
in diameter. In some instances the tunnel is more or less winding, 
and occasionally small cells are excavated along its course. There 
is a tendency for the larva to work in the internodes of the stalk, 
but when necessary it commonly pierces and apparently feeds upon 
the nodes. All parts of the stalk may be tunneled down to and in- 
