41 



tassel and milky ear later in the season; while on cotton, during August 

 and September, the squares and the bolls are eaten. The larvi^e bore 

 directly into the squares and bolls through a small orifice which they 

 make, and eat out 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 (PL III, 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 (PL III, 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 varying 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 egg>^ 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 difficult to detect when 

 deposited on green foliage or on dark- 

 colored corn silks, but on the paler silks 

 one must look very closely before they can 

 be seen. A number of eggs are repre- 

 sented considerably enlarg"ed on Plate IV, 



-. oi i. \lii r. T^ii • ' Fig. 2.— Egg of bollworm; Side 



ligure 2; also see text figure 2. t olio wing 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 shghtly narrower at 

 the extreme bottom and widest about the basal third. Base flat and apex obtusely 

 rounded. 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 

 ribs. Spaces between the ribs transversely furrowed by a series of oval depressions, 

 b.'tween which are fine transverse caringe. 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. 



