41 
tassel and milky ear later in the season; while on cotton, during August 
and September, the squares and the bolls are eaten. The larvae bore 
directly into the squares and bolls through a small orifice which they 
make, and eat oat a varying portion of the contents. This causes 
the squares to flare and drop from the plants, and partially or entirely 
destroys the bolls. The larvae (PI. Ill, figs. 2-7) have molted five 
times and are completely grown in about two weeks during hot weather, 
at the end of which time they leave the food plant and burrow into 
the soil to pupate. In this stage (PL III, fig. 8) another two weeks is 
passed before the adults (PI. Ill, fig. 9) of the next generation emerge. 
After the latter have been out for several days egg laying again begins. 
The larvae and moths are extremely variable in color and markings, 
the former var3dng from a pale green through pinkish to dark brown. 
During the course of the summer in the cotton belt there are from four 
to six generations, while to the north the number decreases to two or 
three in the Central States and probably to a single one in Canada. 
The bollworm passes the winter in its earthen cell beneath the surface 
of the soil, emerging as a moth early in the spring. During the mid- 
dle of the summer in the cotton belt the entire life cycle occupies from 
30 to 35 days only, while in the spring and fall, and also in northern 
localities, it may extend over as much as two months. 
THE EGG. 
DESCRIPTION. 
The eggs of the bollworm are small white objects, scarcely one- 
fiftieth of an inch in diameter. On account of their rather pale color 
they are not very difiicult to detect when 
deposited on green foliage or on dark- ,,.,^i;-. ^^', 
colored corn silks, but on the paler silks ^^\^vf^\ 0^^^^ 
one must look verv closely before they can f'-^ 1 1 \\\S llfC'^^E.^ 
be seen. A number of eggs are repre- '"''•( I'M^ ^^H^P' 
sented considerably enlarged on Plate lY, 
-. ^, 1. jn c. t:^ M ' ' Fig. 2.— Egg of bollworm; side 
figure 2; also see text figure 2. Followmg is and top views (original). 
a more minute description : 
Width, 0.48 mm.; height, 0.50 mm. Shining, waxy white, faintly tinged with 
yellowish. The form is almost dome-shaped, except that it is slightly narrower at 
the extreme bottom and widest about the basal third. Base flat and apex obtusely 
round.ed. Micropyle elevated, somewhat conical; its sides finely longitudinally 
grooved; the margin circularly roughened. 
The sculpture is rough and consists of fourteen primary polar ribs which converge 
toward the apex, where they become obsolete. Between these is a series of second- 
ary ribs which are more irregular, often bifurcate at the apex or joining the primary 
ri})s. Spaces between the ribs transversely furrowed by a series of oval depressions, 
b-tween which are fine transverse carinse. These latter do not rise as high above 
the surface as the polar ribs and are much more delicate. 
The shell is rather tough, and, although the eggs are quite delicate, they are not 
very easily crushed. 
