XXVili INTRODUCTION. 
The celebrated Swammerdam found, by dissection, 
the skins of the larva and pupa enveloped in each 
other, and also the butterfly with all its organs, but 
these in a fluid state. Malpighi discovered within 
the chrysalis of a silkworm, that was only a few 
days old, the eggs of the future moth : and those of 
the Bombyx dispar were discovered by Reaumur 
within the caterpillar, only seven days before its 
change into the aurelia state. 
Although these discoveries disprove all miraculous 
intervention, still we are wonderstruck on reflecting 
that this simple larva, when first it emerges from 
the egg, not thicker than a thread of silk, should 
contain its own triple, or in some cases its octuple 
covering,—the mask of an aurelia and a butterfly, 
folded in the most astonishing manner over each 
other; and besides these, different respiratory and 
digestive organs, a nervous system, and muscles of 
motion peculiar to each stage of its existence. It 
is inconceivable how these successive changes should 
be effected, through the agency of the food which 
it takes into its stomach during the caterpillar state. 
And what is still more incomprehensible, is, that 
this stomach, at one time, is incapable of digesting 
yegetable food, the nectar of flowers being all it can 
