When fully grown, Fig. 15, a and b, which is in about thirty-five to
forty days after emerging from the eggs, they are about two inches
long, with a black head and body, with numerous yellowish hairs on the
surface, with a white stripe along the middle of the back, and minute
whitish or yellowish streaks, which are broken and irregular along the
sides; and there is also a row of transverse, small, pale blue spots
along each side of the back.

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 pupæ, 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.