The plant does not show any sign of decay until the caterpillar is fully grown, when it dies.  The caterpillar, Fig. 19, 2, is about one and one-fourth inches long, of a reddish brown color, with whitish stripes along the body.  The stripes on the sides are not continuous, and the shading of the body varies, being darker on the anterior than on the posterior portion.  When fully grown, Fig. 20, the color is lighter and the stripes are broader.  At this stage of life it burrows into the ground just beneath the surface, and changes into the pupa state.  The pupa is three-fourths of an inch long, and of a mahogany brown color.  The perfect moth appears about the first of September, and there is only one brood in a season.

[Illustration:  Fig. 20.]

The caterpillars feed in the stalks of corn, tomatoes, potatoes, dahlias, asters, and also in young currant bushes, besides feeding on many species of weeds.  By a close inspection of the plants about the beginning of July, the spot where the borer entered, which is generally quite a distance from the ground, may be detected, and the caterpillar cut out without injury to the plant.  This plan is impracticable for an extensive crop, but by destroying the borers found in the vines that wilt suddenly, one can lessen the number another year.

THE PYRAMIDAL GRAPEVINE CATERPILLAR.

Pyrophila pyramidoides (Guen.)

This caterpillar, Fig. 21, is generally found on grapevines early in June, but also feeds on apple, plum, raspberry, maple, poplar, etc.  It is about an inch and a half in length, with the body tapering toward the head; of a whitish green color, darker on the sides; with a longitudinal white stripe on the back, broader on the last segments.  Low down on each side is a bright yellow stripe, between this and the one on the back is another less distinct, and the under surface of the body is pale green.

[Illustration:  Fig. 21.]

The caterpillar is fully grown about the middle or last of June, when it descends to the ground, draws together some of the fallen leaves, and makes a cocoon, in which it soon changes to a mahogany brown pupa.

[Illustration:  Fig. 22.]

In the latter part of July the perfect moth, Fig. 22, emerges, measuring, when its wings are expanded, about one and three-fourths inches; the fore wings are dark brown shaded with lighter, with dots and wavy lines of dull white.  The hind wings are reddish, or of a bright copper color, shading to brown on the outer angle of the front edge of the wing, and paler toward the hinder and inner angle.

The under surface of the wings is lighter than the upper, and the body is dark brown, with its posterior portion banded with lines of a paler hue.

This pest may be destroyed by hand picking, or by jarring the trees or vines on which they are feeding, when they will fall to the ground and may be crushed or burned.