THE LESSEE CORN STALK-BORER. 17 
DURATION OF THE MOLTING PERIOD. 
During the summer months the time required for the larvae to molt 
varies from 12 to 24 hours in all the instars and during the fall from 
12 to 26 hours and sometimes 48 hours. The majority of the larvae 
in fall require only 24 hours. Generally a longer time is required in 
the last instars than in the first ones. 
DESCRIPTION OF ECDYSIS. 
The larva when about to cast its skin becomes pale, sluggish, and 
usually remains motionless in tunnel or tube unless disturbed, and 
even then it is not as active as normally. The first real indication 
that molting has commenced is the appearance of a pale whitish 
patch in the region of the neck. This patch is the outer conjunctival 
layer which, having been loosened, is being unfolded to accommodate 
the growing larva. This patch becomes more and more evident as 
molting progresses. The eyes at this time can be seen through the 
semi transparent conjunctival layer, appearing a little distance back 
of the head mask. The outer layer of the cuticle, having been loos- 
ened throughout, ruptures immediately back of the head mask, 
first on the venter, then rapidly extending laterally and dorsally. 
The larva with wavelike rhythmic motions gradually draws itself out 
of the old cuticular layer. Just at the point when the last joint is 
being extricated the larva bears down with the head and frees itself 
from the mask. 
FEEDING HABITS OF THE LARVA. 
The larva of the species, as its common name would indicate, has 
a habit of boring or tunneling into the stems of growing plants (PI. 
Ill, fig. 3) and feeding within. This manner of feeding is especially 
characteristic where young corn and sorghum plants are attacked. 
The larvae in such cases tunnel into the stalks at or slightly below 
the surface of the ground, through and sometimes up the heart for 
a distance varying from 1 to 2 inches. The bud leaves of such af- 
fected plants die, having been severed from the main plant; Plate 
III, figure 2, shows the appearance of such a plant. The bud leaves 
dry up and wither away. Some of the plants may survive, but 
such plants remain in a dwarfed condition or become deformed and 
one sided. 
Injury to corn in this manner resembles closely the work of the 
southern corn rootworm (Diabrotica 12-punctata Oliv.); however, 
E. lignosellus is an upland species, being found only in the driest 
ol soils, while the corn rootworm breeds generally in the moist 
lowlands. 
In older corn and sorghum, as well as in cowpeas, the damage con- 
sists primarily in the girdling of the stems at or slightly below the 
surface of the ground, but the larvae also tunnel into the stems, 
