LETTER XV. 
HABITATIONS OF INSECTS —continued. 
Tue habitations of insects which I shall next proceed to describe are those 
formed by the united labour of several individuals. The societies which 
thus combine their operations may be divided into two kinds: Ist, those 
of which the object is simply the conservation of the individuals composing 
them ; and 2ndly, those whose object is also the nurture and education of 
their young. To the last head belong bees, wasps, &c. : to the former the 
larvee of some species of moths, whose labours, being the most simple, I 
shall first describe. 
You cannot fail to have observed in gardens the fruit trees disfigured, as 
you would probably think them, with what at first view seem very strong 
and thick spiders’ webs. If you have bestowed upon these webs the 
slightest attention, you must have likewise remarked that they differ very 
materially in their construction from those spun by spiders, inclosing on 
every side an angular space, and being besides filled with caterpillars, 
These are the larva of Porthesia chrysorrheea, and the web which contains 
them is spun by their united labour for the protection of the common 
society. As soon as the cluster of eggs deposited by the parent moth is 
hatched, the young caterpillars, to the number of three or four hundred, 
commence their operations. At first they content themselves by forming 
a sort of lrammock of the single leaf upon which they find themselves 
assembled, covering it with a roof composed of a number of silken threads 
drawn from one edge to the other; and under one or more of these tem= 
porary habitations they reside for a few days, until they are become large 
and strong enough to undertake a more solid and spacious building suffi- 
cient to contain the whole society. In constructing this new habitation, 
they spin a close silken web round the end of two or three adjoining twigs 
and the leaves attached to them, so as to include the requisite space. 
They are not curious in giving any particular form to the edifice: some- 
times it is flat, often roundish, but always more or less angular. The 
interior is divided by partitions of silk into several irregular apartments, to 
each of which there is purposely left an appropriate door. Within these 
the caterpillars retire at night, or in rainy weather, quitting the nest on 
fine days, and dispersing themselves over the neighbouring leaves, upon 
which they feed. Here, too, they repose during the critical period of the 
change of their skins. On the approach of winter the whole community 
shut themselves up in the nest, which, by the addition of repeated layers 
of silk, has at this time become so thick and strong as to be impervious to 
the wind and rain. They remain in a state of torpidity during the cold 
months, but towards the beginning of April are awakened to activity by 
