214 STATES OF INSECTS. 



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 lo), which in most places may be found 

 upon nettles, or those of the Pieris Brassicts, which swarm 

 in cabbages or brocoli 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 larvae 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, ap- 

 pearing only to be fastened by some part of their abdo- 

 men to the body upon which they are fixed a . 



2. The larvae 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 diffe- 

 rent materials. For the sake of method, I shall divide 

 these into two great classes : First, those which form their 

 cocoons entirely or principally of silk; and secondly y 

 those which form them chiefly of other substances. 



To begin with the Jirst. The larvae which inclose 

 themselves in silken cocoons are chiefly of the Lepido- 

 pterous tribes of Bombycidce and Noctuidce ; but a few 



* N. Diet. a" Hist. Nat. w. 591—. 



