PROGRESS EEPOET ON THE EUROPEAN CORN BORER 
71 
DESCRIPTION 
THE EGG 
Average length 0.97 millimeters, average width 0.71 millimeters; 
elliptico-ovate, sometimes nearly circular in contour, thin, more or 
less scalelike, slightly convex on its uppermost surface, flat on its 
undermost surface or conforming 
with the surface of the object 
upon which the egg is deposited. 
Chorion reticulated with fine ele- 
vated lines, which anastomose reg- 
ularly and thereby inclose shallow 
pentagonal or polygonal foveae. 
Eggs when first laid greenish 
white, more or less translucent on 
the periphery, the opacity increas- 
ing centrally where the egg at- 
tains its greatest depth; ordi- 
narily strongly iridescent. In 18 
to 24 hours after deposition there 
appears in the egg a crecentiform 
clear area, slightly excentric in its 
position as viewed from above; 
the balance of the egg becoming 
strongly opaque. Two days before hatching the egg assumes a 
yellowish cast, and soon thereafter the head capsule of the inclosed 
larva is seen, its chitinization proceeding rapidly. Several hours 
____________________ before hatching the cho- 
rion collapses about the 
larva and its shape is 
plainly evident. At time 
of hatching the head and 
thoracic shield are black ; 
the body segments are 
yellowish white. 
The eggs commonly are 
deposited in irregularly 
shaped masses (fig. 35), 
and less frequently in 
regular rows. The mass 
is flat and easily remov- 
able from the object upon 
which it is laid. The eggs in the mass are overlapped, shingle-like, 
with successive eggs deposited by the female. According to records 
obtained, they range from 1 to 162 in number, 15 to 20 eggs repre- 
senting the average size of the mass. 
Fig. 35. — Egg mass of the European corn 
borer. Greatly enlarged 
Fig. 36. — Larvae of the European corn borer. 
Slightly enlarged 
THE LARVA 
Full-grown larva (fig. 36), average length 20 to 23 millimeters, 
width 3 to 3.5 millimeters. Body cylindrical, abdominal segments, 
except 9 and 10, grooved transversely. Body dirty white, shading 
from light brown, or dark brown, to pink on the dorsum. Dorsum 
heavily granulated, skin granulations extending to the pleurae, heav- 
ily granulose along dorso-median line, taking the form of a band or 
