As they move about they form a continuous thread of silk from a fleshy tube on the lower side of the mouth, which is connected with the silk-producing glands in the interior of the body, and by means of this thread they appear to find their way back from the feeding grounds.  It is also by the combined efforts of all the young from one belt of eggs that the tents are formed.

These caterpillars do not feed during damp, cold weather, but take two meals a day when it is pleasant.

After reaching their full growth, they leave their tents and scatter in all directions, seeking for some protected place where each one spins its spindle-shaped cocoon of whitish silk intermingled with sulphur colored powder, Fig. 15, d.  They remain in these cocoons, where they have changed to pupae, from twenty to twenty-five days, after which the moths emerge, pair, and the females lay their eggs for another brood.

Several remedies have been suggested, a few of which are given below.  Search the trees carefully, when they are bare, for clusters of eggs; and, when found, cut off the twigs to which they are attached, and burn them.

As soon as any tents are observed in the orchard they should be destroyed, which may be readily and effectually done by climbing the trees, and with the hand protected by a mitten or glove, seize the tent and crush it with its entire contents; also swab them down with strong soapsuds or other substances; or tear them down with a rounded bottle brush.

Burning with a torch not only destroys the caterpillars but injures the trees.

It should be observed, however, since the caterpillars, are quite regular in taking their meals, in the middle of the forenoon and afternoon, that they should be destroyed only in the morning or evening, when all are in the tent.

Another remedy is to shower the trees with Paris green in water, in the proportion of one pound to one hundred and fifty gallons of water.

THE FOREST TENT CATERPILLAR.

Clisiocampa disstria (Huebner.)

This species, commonly known as the forest tent caterpillar, closely resembles the apple tree tent caterpillar, but does not construct a visible tent.  It feeds on various species of forest trees, such as oak, ash, walnut, hickory, etc., besides being very injurious to apple and other fruit trees.  The moth, Fig. 17, b, expands an inch and a half or more.  The general color is brownish yellow, and on the fore wings are two oblique brown lines, the space between them being darker than the rest of the wing.  The eggs, Fig. 17, c and d, which are about one twenty fifth of an inch long and one fortieth wide, are arranged, three or four hundred in a cluster, around the twigs of the trees, Fig. 17, a.  These clusters are uniform in diameter and cut off squarely at the ends.  The eggs are white, and are firmly fastened to the twigs and to each other, by a brown substance, like varnish, which dries, leaving the eggs with a brownish covering.