STATES OF INSECTS. (Larva.) 227 
magnificent silk-moth, Attacus Paphia, actually forms a 
solid silken stalk to its cocoon, an inch and half in length 
and a line in diameter, fastened by the other extremity 
to a twig, which it closely surrounds as if with a ring, 
at first sight resembling a fruit of a very singular ap- 
pearance*. I have specimens of this cocoon with both 
stalk and ring. Most larvee spin their cocoons in soli- 
tude: some of those, however, which live in society do it 
close together under their common tent. 
There are other cocoons that should be noticed here, 
such as those formed by the larva of Sygena Filipendule, 
and some moths, saw-flies, and beetles (Donacia), &c. 
These are formed of a substance which seems more ana- 
logous to gum than silk, yet furnished from the silk 
reservoirs, and usually present the appearance externally 
of parchment or membrane. That of the insect first 
mentioned is coated, however, with a slight interior silken 
lining ; as indeed are almost all cocoons, of whatever 
substance. 
The second class, into which I have divided larve that 
inclose themselves in cocoons, includes those which form 
their coverings not solely or principally of silk, but in 
which other materials are mixed more or less. The co- 
coons of some of these larvae are merely composed of a 
few leaves slightly tied together, either irregularly, or ar- 
ranged, particularly when they are of a linear figure, 
with considerable symmetry. The grubs of many beetles, 
as of the rose-beetle, Cetonia aurata, &c. prepare them- 
selves a cocoon, composed of earth, pieces of rotten 
wood, and any substances within their reach; which 
* Linn, Trans. vii. t. i. f, 5, 6. 
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