4 FARMERS” BULLETIN 133. 
LIFE HISTORY OF THE SPECIES. 
Beetles of the corn and cotton wireworm (fig. 1, @) are abroad in 
the fields from early June until the last of August. The eggs (fig. 2), 
which are laid in groups of from 3 to 20 in the soil about the roots 
of corn, cowpeas, and other food plants, are deposited, for the most 
part, during late June and July. These hatch in from 8 to 11 days 
into the young wireworms or larve (fig. 1, 6) which immediately com- 
mence feeding upon the roots. The exact duration of the period of 
development in the soil has not yet been determined, but the informa- 
tion now at hand indicates that the species lives in the larval stage 
for two years and possibly three. It is true that adults are to be 
found each year, but this is probably due to overlapping broods. 
During May or June each full-grown larva constructs a small earthen 
cell in the soil and in this it changes to a pupa (fig. 3). The pupal 
stage averages 12 days in length and during this time the pupa is 
almost motionless and takes no food. After this it transforms to the 
adult or beetle. As is usually the case, the duration of the egg and 
pupal stages varies with temperature and moisture conditions. 
HABITS OF THE LARVA, OR WIREWORMS. 
The larve, or wireworms, feed upon the roots of their food plants 
throughout the summer months and up to about the first of October, 
and during this time are found within 18 inches of the surface of the 
ground, the depth depending upon the moisture content of the top - 
soil. During a hot, dry spell the wireworms remain from 12 to 18 
inches below the surface, but after a rain they can be found within 2 
inches of the surface. 
With the approach of cold weather they begin a general down- 
ward movement, which accounts for the farmer’s inability to locate 
them during the late fall and winter months. At Charleston, Mo., 
December 1, 1914, they were found in the sand at the remarkable 
depth of 5 feet. This appeared to be the average depth at which they 
remained during the winter in this locality, observations showing the 
depth to vary from 4 to 6 feet. From these facts it will be seen that 
fall or winter plowing would be useless as a control or remedial 
measure. 
By the last of February in some localities, or as soon as winter 
breaks up, the larve gradually make their way to within 2 to 3 feet 
of the surface. By the middle of April they are numerous within 6 
inches of the surface of the ground. From the time the larve travel 
downward in the fall until they return to the top soil they eat prac- 
tically nothing. In laboratory experiments, larvee remained alive and 
healthy in cages of moist pure sand, without organic food, for six 
months. 
