70 



gnawed in one side near the base and the contents eaten out, leaving 

 onh^ a hollow shell still retaining its original shape (see PI. IX, 

 fig. 4). Subsequent injury to squares is done in the same way, 

 except that the hole eaten by the full-grown larva is considerably 

 larger. Bolls are scarcely ever attacked b}^ newly hatched larvae, 

 although the latter can subsist on them without difficulty in the 

 absence of other food. Larvae one-third grown or larger may bore 

 into the bolls at a point not far from the base or farther up on the 

 side, as shown in figures 1 and 2, Plate X. If the boll is small, like the 

 one shown on Plate IX, figure 5, the entire contents are appropriated, as 

 in the case of a square, but if it is large usuall}^ only one or two 

 ''locks" are badly eaten (see PI. X, figs. 3 and 4). When the larva 

 leaves the boll its exit is most generally made through the entrance 

 hole, although a second opening is sometimes made. The excrement 

 left in the boll by the departing larva usually stains what fiber may be 

 left in that lock to a dark brown, and often favors fermentation and 

 the development of mold, which quite often ruins the boll entirel3^ 

 If two or three locks have been destro3^ed the boll may open more or 

 less imperfectly, as shown on Plate X, figure -^, or fail to open at all. 

 In such bolls the large hole made by the bollworm is always plainly 

 to be seen. 



The flowers are often attacked soon after the}^ have opened and 

 before the petals have become pinkish. Usually the pistil, stamens, 

 and ovary are destroyed and the flower ruined (see PI. IX, fig. 2). 

 The stamens especially seem to be very well liked and injury ma}^ be 

 confined to the destruction of these (see PL IX, fig. 1). 



The leaves of the cotton plant are not fed upon by the bollworm 

 unless squares and bolls are ver}^ scarce. Under such conditions the}^ 

 take very readily to leaves, eating them in a way similar to the cotton 

 worm {Alabama [Aletia] argillacea). In the large field cage in the 

 laboratory garden at Paris a method of feeding not noticed elsewhere 

 was observed. The squares and bolls had practicalh^ all been 

 destroyed and the large larva?, l)oring through the axillar}^ buds into 

 the stem, caused it to break at that point and wither and die. 



CHARACTER OF INJURY TO OTHER PLANTS. 



The feeding habits of the bollworm on other plants than corn and 

 cotton are rather bej^ond the scope of the present bulletin and can only 

 be briefly referred to. 



On tomatoes the green fruit is usually the part chosen, the young 

 larva boring through the skin at almost any place, while the older 

 ones prefer to enter near the insertion of the stem (see PI. XI, fig. 2). 



Tobacco is injured at the growing tips or ''bud " early in the season 

 (see PI. XI, fig. 1), but later, if the plants are not topped, the green 

 seed pods are preferred. 



