The Bulletin 
95 
feed upon some of the wild food plants, but close observation fails to 
show any especial increase in their numbers in such situations. ISTeitlier 
can any be found in the usual hibernation situations save young beetles 
which have evidently not yet emerged from their pupal cells. 
s ‘ 
Figure 61. Adult lateral view. X6. 
DIURNAL ACTIVITY 
The diurnal activity of corn bill bugs in the field was made a special 
point for investigation during the summer of 1912, and since that time 
many additional observations have been made which support the con¬ 
clusions drawn at that time. In making these observations, 627 adults, 
329 of which were females and 298 were males, were marked in various 
ways and studied throughout the month.of July and part of August. 
These adults, it is believed, represented all of the individuals present 
on a plat of about one-third of an acre in extent. Observations were 
made at various times for every hour of the day and night. From 
these observations we have concluded that there are two main periods 
of activity for the corn bill bug, the activities for the most part con¬ 
sisting of feeding and egg laying for the female and feeding and mating 
for the males. For a fuller discussion of these activities, see habits of 
adults below. Two main daily periods of activity are followed by two 
periods of inactivity, when the bill bugs crawl away under any shelter 
that may present itself, such as clods, partially buried sticks or pieces 
of cornstalks and stones. The activities vary somewhat from month 
to month and from day to day. But the activities on a cool, cloudy 
day late in the season approximate the activities on a warm, bright 
day early in the season. I have attempted to reduce all of these ob¬ 
servations to the form of a curve (Fig. 62). 
In order that all of the observations made during the summer of 
1912 and during the following summers might be correlated, the ob- 
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