IMPERFECT SOCIETIES OF INSECTS. 301 
ments, which is pitched over some of the plants that constitute their 
food, and shelters them both from the sun and the rain, When they have 
consumed the provision which it covers, they construct a new one oyer 
other roots of this plant; and sometimes four or five of these encamp- 
ments may be seen within a foot or two of each other. Against winter 
they weave and erect a stronger habitation of a rounder form, not divided 
by any partitions, in which they lie heaped one upon another, each being 
rolled up. About April they separate, and continue solitary till they 
assume the pupa. i 
Reaumur, to whom J am indebted for this account, has also given us 
an interesting history of another insect, the gold-tail moth (Porthesia 
chrysorrhaa) before mentioned, whose caterpillars are of this description, 
They belong to that family of Bombycide which envelop their eggs in 
hair plucked from their own body. As soon as one of these young cater- 
pillars is disclosed from the egg, it begins to feed ; another quickly joins it, 
placing itself by its side; thus they proceed in succession till a file is 
formed across the leaf: — a second is then begun ; and after this is com- 
pleted a third, —and so they proceed till the whole upper surface of the 
leaf is covered : — but as a single leaf will not contain the whole family, 
the remainder take their station upon the adjoining ones. No sooner 
have they satisfied the cravings of hunger, than they begin to think of 
erecting a common habitation, which at first is only a vaulted web, that 
covers the leaf they inhabit, but by their united labours, as I have de- 
scribed in a former letter, in due time grows into a magnificent tent of silk, 
containing various apartments sufficient to defend and shelter them all 
from the attacks of enemies and the inclemency of the seasons. As our 
caterpillars, like eastern monarclis, are too delicate to adventure their feet 
upon the rough bark of the tree upon which they feed, they lay a silken 
carpet over every road and pathway leading to their palace, which ex- 
tends as far as they have occasion to go for food. To the habitation just 
described, they retreat during heavy rains, and when the sun is too hot: 
—they likewise pass part of the night in them ; — and, indeed, at all times 
some may usually be found at home. Upon any sudden alarm they 
retreat to them for safety, and also when they cast their skins : —in the 
winter they are wholly confined to them, emerging again in the spring: 
but in May and June they entirely desert them ; and, losing all their love 
for society, live in solitude till they become pupa, which takes place in 
about a month. When they desert their nests the spiders take possession 
of them ; which has given rise to a prevalent though most absurd opinion, 
that they are the parents of these caterpillars." 
With other caterpillars the association continues during the whole of 
the larva state. De Geer mentions one of the saw-flies (Serrifera) of this 
description which form a common nidus by connecting leaves together with 
silken threads, each larva moreover spinning a tube of the same material 
for its own private apartment, in which it glides backwards and forwar«s 
upon its back.2 I have observed similar nidi in this country ; the insects 
that form them belong to the Fabrician genus Lyda. 
A small East Indian hair-streak butterfly (Zecla Isocrates), of whose 
economy Mr. Westwood has given an interesting account, resides in the 
larva state in small societies of at least seven or eight individuals in the 
1 Reaumur, ii. 123. 2 De (Gooey, ii, 1029, 
