LASIOCAMPIDS. 139 
and the old skins of the inhabitants. The tents (Fig. 138, 
Plate XVII), when opened, will be found to contain numer- 
ous blackish caterpillars with yellow and bluish spots and 
covered with very fine grayish hairs, which prevent any 
moisture from reaching their skins. The illustration shows 
two of the full grown caterpillars, which are rather pretty 
insects, if caterpillars can be so called. When hatched they 
measure about one-tenth of a inch in length; they are black- 
ish and covered with fine gray hairs (Fig. 144, Plate X XII). 
They feed on the young and tender leaves, and eating on an 
average two leaves a day, the young of one pair of moths 
consume from ten to tweive thousand leaves, and as it is 
not uncommon to findfrom six toeight nests on a single tree 
not less than seventy-five thousand leaves are devoured, a 
loss which no tree can long endure. 
As the caterpillars grow they cast their skins from time 
to time. In about thirty-five or forty days they have 
reached their full size; they are about two inches long, with 
a black head and body, having numerous yellow hairs on 
the surface. A white stripe marks the middle of the back, 
and minute white or yellow broken and irregular streaks 
are found along the sides. Along each side of the back is a 
row of small transverse pale-blue spots. Fig. 137, Plate 
XVII, gives an illustration of the larva. 
While young the caterpillars are social in their habits. 
When they leave their tent to feed, which they do twice 
every day, they move as a regular army, and as they go 
they spin a continuous thread of silk from a fleshy tube on 
the lower side of the mouth, which is connected with silk- 
producing glands in the interior of the body. By means of 
this thread they find their way back to the tent, which is 
the product of the combined efforts of all the caterpillars 
from one ring of eggs. The caterpillars feed only on warm 
and dry days; during cold and damp weather they remain 
in the tent. As soon as full grown they leave their home 
and scatter in all directions, each searching for some pro- 
