3 22 
The Ohio Naturalist. 
[Vol. XIV, No. 7, 
EXCAVATING THE CAVITY. 
While excavating the cavity, the insect retains a firm attach¬ 
ment to the corn by clasping the surface, chiefly with the spines 
on the distal ends of the tibiae. During the entire process, one of 
the fore legs is in almost constant motion as though endeavoring 
to obtain a better foothold. The operation of digging is accom¬ 
plished by giving an oscillating motion to the thorax on the first 
pair of legs as an axis, which results in an up-and-down movement 
of the proboscis. At the same time, the head is turned from side 
to side, thus adding a rotary motion to the proboscis. This 
operation continues until the hole is partially dug, when the 
proboscis is lifted nearly to the surface, after which the sides are 
Figure 1. Longitudinal section of cavity showing egg and plug in place. 
cut down, enlarging the excavation. When the bottom is again 
reached, the former movements are resumed. These movements 
often end with sharp jerks as though pieces of the material were 
being broken off. The work of excavating is continued until the 
depth of the cavity is equal to the length of the proboscis, when 
the weevil stops digging, and prepares to deposit the egg. During 
the process of digging, that part of the proboscis that extends into 
the cavity is clean, but chewed material collects about the mouth 
of the cavity and on the portion of the proboscis above. 
