24 Farmers’ Bulletin 1294. 
on the underside, although infrequently on the upper side, of a leaf, . 
or on the stem of the host plant. Each egg overlaps the adjoining 
eggs in the manner of shingles. The female moths of this brood 
deposit an average of about 350 eggs each, but individual females 
under observation deposited as many as 724 to 1,192 eggs each. The 
average length of life of the moths of 
both sexes is about 18 days. 
The egg is nearly flat and about one 
twenty-fifth of an inch in diameter. It 
is white when first deposited, but later 
changes to pale yellow, becoming darker 
just before the young larva or borer 
hatches therefrom. 
The eggs hatch in from 4 to 12 days, 
with an average of about 7 days, the 
length of the egg stage varying with the 
Fic, 19, Larva of the European climatic conditions. The newly hatched 
borer is about one-sixteenth of an inch 
long, with a black head and a pale yellow body, bearing several 
rows of small black or brown spots. It feeds for a few days upon 
the surface of the leaf, near its place of hatching, but soon enters the 
plant and completes most of its development therein. It may also 
migrate to other plants by crawling or spinning a suspending thread. 
During its growth the borer molts, or 
changes its skin, five or six times, grad- 
ually becoming darker and increasing in 
size until it is of the same appearance 
and size as the overwintering borer pre- 
viously described. By the third week of 
July, or about 38 days after hatching 
from the egg, the borer becomes full 
grown and changes to the pupa, or rest- 
ing stage, usually inside its tunnel in the 
host plant. About 11 days later, during 
the last part of July, or in early August, 
the moths emerge from these pupe and 
deposit their eggs as described for the 
first brood of moths in June. Many of 
these eggs are deposited directly upon or 
closely adjacent to the partly developed 
ears of field corn and of late sweet corn. 
An average of about 450 eggs are de- 
posited ‘by each female moth of this :see-) Ps. 20 Een 
ond brood, but individual females under Views. About three times natu- 
observation deposited as many as 1,934 — T#! Size (Caffrey.) 
egos each, 
The eggs of this generation hatch in about 7 days, and the resulting 
borers attack the plant in a manner similar to that described for the 
first generation. 
At this time the injury to the ears of field corn and late sweet corn 
may be very great, due to the fact that many of the borers make their 
way directly into the ears after hatching from the egg, and feed 
within the partly developed ear. 
