68 
The Bulletin 
however, 169 out of the 221 larvae observed, or about 77 per cent, passed 
through their larval development between the 26th and 37th days after 
hatching. 
CHARACTER OF INJURY CAUSED BY LARYdE 
The most noticeable result of the presence of the larvae in stalks 
of corn is the stunting of their growth. Nearly always in fields of any 
size there are some stalks that escape injury, due to a variety of con¬ 
ditions, and these stalks always tower above their neighbors like giants 
among a group of pigmies. Stalks that have worms present early in 
their development usually are injured to such an extent that they die. 
Stalks that are attacked later may grow to a certain extent after the 
attack by the larvae, but one usually has no trouble in deciding which 
stalks in a given field are infested by larvae and which ones are not. 
These secondary effects upon the stalks are found in the abnormal 
growth that the stalks make. In addition to being stunted, the stalks, 
in severe attacks, are twisted out of all semblance to a cornstalk. This 
usually results in an attempt to produce suckers, but usually these 
suckers are not able to expand their leaves, and appear like some great 
abnormal growth on the sides of the stalk. (Figs. 42, 43, and 44.) 
When the larvae are working externally around the roots (Fig. 45), 
they seem to produce a distinct scar or split which extends up along the 
side of the plant, often to a height of several inches above ground. 
These scars are frequently shallow, but often they are very deep and 
seriously retard the normal growth of the plant. They appear to be 
out of all proportion both in length and in depth to the actual injury 
caused by the larvae. 
Another source of injury directly attributable to the larvae is the 
weakening of the stalks to such an extent that they are blown over by 
heavy winds. This is more noticeable in fields that are only moderately 
infested by corn bill bugs than it is in fields that are badly infested, 
due to the fact that badly infested fields do not produce stalks large 
enough to be blown over by the wind. 
Internally the larvae upon hatching from eggs deposited in the stalk 
seem always to take a course diagonally inward and downward toward 
the center of the stalk, coming to lodge eventually in the tap-root 
(Fig. 46). While the larvae are small, they do not seem to injure the 
stalk to any great extent, but as they increase in size they frequently 
eat away the entire tap-root (Fig. 47). This, of course, results in the 
stunting of the growth of the plant as noted above. This internal 
injury is nearly always confined to the tap-root and the portion of the 
stem below ground. Occasionally larvae after working downward to 
the tap-root, turn and work upward sometimes to a considerable distance 
above ground. The causes behind such behavior are difficult to deter¬ 
mine, as it certainly is not always due to a lack of food, for frequently 
larvae will work upward in stalks where there is an abundance of food 
