558 Journal of Agricultural Research voi. xxvi. no. h 
LIFE HISTORY AND DEVELOPMENT 
The insect hibernates in the adult stage beneath piles of rubbish, grass, 
weeds, and refuse, or buried in soft sandy soil, and in the burrows of small 
mammals; it also hibernates in the larval stage, buried deeply in the soil. 
In the latitude of southern Kansas the adult is abroad in the fields depos¬ 
iting eggs in early spring, and is present in the fields until late November. 
Some of the adults have been known to live two or three years. The egg is 
deposited in soft loose soil at a depth of about three-fourths of an inch to 
i inch. Frequently from io to 60 eggs are found in a single nest. The egg 
hatches in from 8 to io days, depending on the moisture and temperature, 
and the young larva a short time thereafter begins to feed very actively 
upon vegetable tissue and roots in the soil. Where development occurs 
under favorable weather conditions and with adequate food supply, the 
larva grows rapidly, reaches maturity, and enters the pupal stage in about 
no to 130 days, though this period may be accelerated or prolonged by 
abnormal conditions. The pupal stage continues for a period varying 
from 10 to 22 days, during which time the insect is comparatively mo¬ 
tionless in an earthen cell at a depth of about 3 inches in the soil and takes 
no food, and at the end of this period transformation to the adult stage 
occurs. This adult in turn often produces another generation of larvae 
in late summer. Such larvae when about half grown (and at a depth of 
about 2 to 5 inches in the soil at wheat-seeding time) reach their period of 
greatest destructiveness about the time the newly sown fall wheat is 
coming through the ground. Numbers of the larvae of this generation 
usually overwinter as larvae at considerable depths beneath the ground or 
in loose soil beneath refuse. Some of these larvae have been found in No¬ 
vember at a depth of 7 inches and in December at a depth of 14 inches 
in the soil. It should be noted that there is considerable overlapping of 
generations, hence larvae of widely varying size often coexist in the same 
field. 
The newly hatched larva does not immediately become active but 
remains for a little while in the soil, at the place where the egg was 
hatched and in the cavity formerly occupied by it. The toughness of the 
eggshell is indicated by the fact that the empty shell retains its shape 
for some time after the larva has emerged therefrom. The integument 
of the newly hatched larva is rather tender but nevertheless enables it 
to survive rather rough handling. When newly hatched the larva 
averages 2.5 millimeters in length and about 0.3 millimeter in width, 
and is semiopaque white. The general proportions of the newly hatched 
larva do not vary to any noticeable degree from those of the older larva, 
but there is an occasional slight variation in size. The larva begins to 
feed lightly not long after hatching, and appears to grow with greatest 
rapidity during the first three or four weeks, as it more than doubles in 
size during this period. Following the second molt the rate of growth 
becomes less marked. Larvae invariably are present in infested fields in 
greatest numbers in the vicinity of straw stacks, or in the absence of 
these, in the neighborhood of or beneath scattered bundles of grain 
which contain such a large percentage of weeds that they have been 
discarded and left behind by the harvesters. It has been repeatedly 
noticed that the infestation in many fields invariably appears to originate 
and spread from such straw stacks and is always more severe in their 
vicinity. In fields not sown to wheat the larvae are not found scattered 
generally over the field but are usually grouped in numbers in the soil 
