STATES OF INSEcTS. (Larva.) 213 
neeuvres by which these curious modes of suspension are 
effected, you may be readily gratified. It is only neces- 
sary to collect and feed until their metamorphosis the 
black spinous caterpillars of the common peacock-but- 
terfly (Vanessa Io), which in most places may be found 
upon nettles, or those of the Pontia Brassica, whichswarm 
in cabbages or broccoli in every garden. The former will 
exhibit to you a specimen of vertical, the latter of hori- 
zontal suspension. It should be observed, however, that 
to hit the precise moment when these processes are go- 
ing on, it is necessary to feed a considerable number of 
the larvee of each kind; some one of which, if you watch 
them narrowly when they have attained their full growth, 
you will scarcely fail to surprise in the act. 
I must observe here, that although the vertical and 
horizontal are the two principal positions in which cater- 
pillars suspend themselves, yet that others are inclined 
at various angles; and some are attached with less art, 
appearing only to be fastened by some part of their ab- 
domen to the body upon which they are fixed’, 
2. The larve whose procedures I am in the next place 
to describe, are those which, previously to assuming the 
pupa state, inclose themselves in cases or cocoons of dif- 
ferent materials. For the sake of method, I shall divide 
these into two great classes: First, those which form their 
cocoons entirely or principally of sz/z ; and Secondly, those 
which form them chiefly of other substances. 
To begin with the first. The larvee which inclose 
themselves in sz/ken cocoons are chiefly of the Lepido- 
* N. Dict. d’ Hist. Nat. vi. 291—. 
