54 
SOCIAL NESTS. 
soon as his cattle have eaten up the grass round 
it, and goes in search of fresh pasture. 
In summer, the web of the tent is so fine as to 
he transparent; hut before the winter comes, the 
caterpillars spin more threads, and make them 
into a round hall, thick and strong, so that you 
cannot see through it. Here they coil themselves 
up, and lie huddled together in one apartment, 
waiting for warmer days, and brighter weather. 
But you will he most interested to hear about 
the processionary caterpillars.* They are natives 
of France, and feed upon the oak. Their nest is 
always found upon the trunk, and as the silk 
it is made of is of a grey colour, it looks, at a 
distance, like a mass of lichen. 
There are about eight hundred caterpillars in 
a family; and while they are young they have no 
fixed habitation, but encamp sometimes in one 
place, and sometimes in another. As soon how¬ 
ever as they are grown up, they weave a tent in 
common, and leave a single opening, that serves 
them for a door. After sunset, they march out 
with such regularity, that they are like a troop 
of soldiers. The one that is nearest the door 
goes first, and heads the procession. When he 
stops they all stop, and when he goes on they all 
go on. He is followed by three or four cater- 
* Bombyx processionale. 
