THE BOMB YCINA. 
>15 
three darkish bands, give it a very quiet appearance. It appears 
in the woods about the months of August and September. The 
females lay their eggs in masses upon the trunks or larger 
branches of oak trees, and cover them with the hairs from the 
body. The caterpillars are hatched in the month, of May, 
and are collected in families which contain hundreds of mem- 
bers. They form an irregular web, in which they remain very 
quietly during the daytime, but in the evening they crawl upon 
the foliage and eat voraciously. When they have finished their 
meal they either return to their old home or make another. 
One of these nests may cover a considerable part of the trunk of 
a tree, and it consists of several layers of web, one over the 
other, but very intimately woven together. Every observer must 
be struck with the manifest order and routine observed by these 
caterpillars in their peregrinations. If the nests are examined 
during the daytime all is quiet within, and the caterpillars 
are crowded one upon the other, and are almost motionless. 
As soon, however, as the sun has gone down there is a slight 
movement, and then a general waking up. A caterpillar leaves 
the nest, and commences climbing the trunk. It is followed by 
another, and this one by a third, and then comes a rank of three 
or four individuals, which is followed by one of many more, and 
so on. 
The ranks go on increasing in their numbers in a very regular 
manner, but the column at last becomes confused. There may 
be two or three caterpillars instead of one in the second and 
third ranks, but one larva invariably leads the array in its curious 
procession. After feasting, the same order is taken up, and the 
host of caterpillars returns to camp in the same formation. Even 
if they move from one branch to another this procession is wit- 
nessed, and yet nothing distinguishes the leader from the others, so 
that the instinct which admits of these manoeuvres is very remark- 
able. When the larvae have attained their full growth they gra- 
dually increase the strength of the walls of their nest with their 
moulted skins, and then each one makes its cocoon inside and be- 
comes transformed. In the engraving, which represents a scene in 
the Bois de Boulogne, near Paris, the processional caterpillars are 
on the march and are being attacked by a large beetle and its 
