96 NEW YORK STATE MUSEUM 
leaves, lining them with silk, and inclosing them with a mass of 
silken threads. These tents [pl. 1, fig. 7] are so firmly secured to 
the twigs that they can not be removed without considerable force. 
The young caterpillars emerge from their winter retreats 
before the leaves begin to appear, often attack swelling buds and 
complete their growth in the early part of June, when they trans- 
form to pupae. The full grown caterpillars [pl. 1, fig. 3] range 
from 1 inch to 114 inches in length. The pale brown head is 
mottled with dark brown and has reddish brown hairs scat- 
tered over its surface. The body is dark brown or black 
with numerous fine, duli orange or gray spots over the surface, 
which are most pronounced on the second, third and fourth 
segments. Long reddish brown, finely barbed hairs arise from 
all the tubercles, and white branching hairs from the upper side 
of the latter tubercles on segments 4 to 12 inclusive. These 
white hairs form elongated white spots along each side and are 
one of the most striking characteristics of this caterpillar. The 
subdorsal and lateral tubercles on segments 4 to 12 inclusive 
‘are covered with fine, short spines of uniform length. There is 
a bright red retractile tubercle on the top of the 10th, and also 
one on the 11th segment. 
The pupae are 34 inch in length, dark brown in color and with 
fine, yellowish brown hairs [pl. 1, fig. 4] scattered over the 
surface. 
Habits of the caterpillars. The following account of the habits 
of these caterpillars is taken from a bulletin by Fernald and 
Kirkland, and is as follows: 
The young caterpillars of the brown tail moth, after hibernat- 
ing in the tents which they construct at the tip of the branches, 
emerge inthespring and feed downward towards the main 
branches and trunk, leaving the naked twigs bearing the gray 
tents at the ends, a conspicuous evidence of the presence of this 
insect. They eat the entire leaf except the midrib, and, in leaves 
having strong ribs, like those of the sycamore maple, all the 
larger ribs are left untouched. When the caterpillars are numer- 
ous they devour not only the buds, leaves and blossoms, but even 
the green fruit. 
The caterpillars are quite gregarious up to the later stages of 
their growth, when they disperse to some extent; but when they 
occur only in moderate numbers, they retain their gregarious 
