21 



portion to the natural requiremeut of organic arrrangement, 

 and this you will presently observe when I compare some 

 of the peculiarities in the nervous system in the larva with 

 those in the perfect insect. 



Having now briefly glanced over the various organs 

 belonging to the caterpillar, I will merely add, before we 

 procaed to its raetamorphosi», that in changing its skin all 

 the external organs come away with it, as also the lining 

 membrane of the spiracles, a portion of that of the tracheal 

 and of the mouth, and all are replaced in the fresh clothed 

 insect. 



The last skin has now been shed, the larva has rapidly 

 increased in size, its final meal has been eaten, its last par- 

 ticle of food digested ; it now by instinct, or say rather by a 

 marvellous power implanted by a beneficent Creator in its 

 little system — a power, arrogant as we are in our constant as- 

 sumption over the brute creation, we are entirely at a loss to 

 comprehend or understand, — seeks the retirement of solitude, 

 and under some carefully sheltered nook prepares for its 

 change : each species, according to its peculiar habits, shows 

 that one guiding principle is leading to a definite object, 

 protection from harm, during the period it is incapable of 

 locomotion, or protecting itself from that host of enemies 

 that naturally prey upon it — wise determinating principle, 

 careful forethought, wonderful instinct — why not reason f 



Some now spin cocoons and enclose themselves in a 

 shroud of silk, of which we despoil them for the adorning 

 and covering of our own persons. Some bite off their long 

 hairs and weave them up in their case ; some add particles 

 of wood, rough bark from trees, sand or earth ; others sus- 

 pend themselves round the waist with a silken girdle; 

 others by the tail ; others delve into the soil. Thus you 

 see there are various ways in which they proceed, all tend- 

 ing to one result, the pupa state — illustrations of which are 

 on the table for your inspection. 



At this period of the larva's existence— on the eve of its 

 change to a pupa — we shall find upon examination some 

 important alteration. Thus, on thcsccond and thirdscgmcnts, 



