6 BULLETIN 708, U. S. DEPARTMENT OF AGRICULTURE. 
much less important as a means of protection. Fortunately, this 
did not appear to be the case, as is shown by he data given in 
Table ITI. 
TaBLe III.—Relative amount of damage done to corn by weevils and by beetles. 
Percentage of— . 
| Total 
Infestation. number : 
ofears, |22tS With jy maced 
damaged kernels 
kernels. 
Weevils'and beetles together: 2.2.25. 252-22 ee eee | 135 100 60 to 75 
Beetlesialone .s 62 2522 Sos kos Sa a ee eee eae | 60 Boe Trace. 
From 60 to 75 per cent of all the kernels on the 135 ears infested 
with weevils and beetles together were seriously damaged. Of the 
60 ears infested with beetles alone, 5 per cent were damaged by 
something. It is possible that worms or other insects not present 
-at the time of the examination might have been the cause of this 
damage. At any rate the damage amounted to a mere trace on 11 
kerhels. It is evident, therefore, that the beetles when alone were of 
no practical importance in the corn studied. The 11 kernels whose 
damage is in question were softer than most of those in the varieties 
used in these studies. If the beetles did this damage, then it is 
probable that they did so because the comparative softness made it 
possible. Other investigations have shown that some of the com- 
paratively soft-grain varieties of corn from outside the areas that are 
badly infested with grain insects may be directly damaged by beetles. 
This again suggests that kernel density may determine whether 
direct damage from beetles is possible, and emphasizes the importance 
of using adapted corn which may involve protective factors that 
have not yet been clearly recognized. Because of the importance 
of adapted varieties for practical purposes this publication is confined 
to the results with such varieties, and since the beetles were not an 
important damaging factor in this connection, these insects are not 
further considered here. 
The lots of corn-considered in Tables I and II were grown in the 
same plat and harvested at the same time, and were as comparable 
as 1t is possible for two lots of ears to be under similar circumstances. 
As the lot considered in Table I was examined for infestation at 
harvest’ time (October, 1915), and the lot considered in Table II was 
examined for infestation after about 10 months in storage (August, 
1916), the differences between the percentages of infestation found at 
the time of examination should represent the gain in infestation 
during storage. The percentages of weevil infestation shown in 
Tables I and II are compared in Table IV. 
