INSECTS. 
1G1 
great tropical Moths and Butterflies, some of which expand 
eight or nine inches, must bo vastly more numerous, 
since the size of the scales does not at all depend on the 
dimensions of the wing. 
The whole Class of Insects is subject to metamorphosis ; 
that is, the same individual animal in the course of its 
progress from infancy to adult age assumes an appearance 
and form, with organs both external and internal, different 
at different stages of its life. In none of the Orders are 
these transformations more remarkable than in that which 
we are now considering, the elegant Order Lehdoptera, 
the Butterflies and Moths. 
The parent Butterfly, seeking on restless wing for the 
plant which shall form a suitable food for her unborn 
young, at length lays on its leaf an egg, cementing the 
tiny atom to its surface by a natural glue, which imme- 
diately hardens. In a few weeks a minute Caterpillar 
breaks from the prison, and frequently commences exist- 
ence by devouring with its powerful jaws the horny egg- 
shell which it has just vacated. But vegetable matter is 
its proper diet, and, by the providence of its mother, it 
finds its habitation cast on a plant which is suitable for 
its nourishment ; it is like an ox placed in the midst of 
an unbounded pasture. 
The little worm feeds, and feeds, and foods, with won- 
derful voracity : it does nothing else in short, and conse- 
quently grows with rapidity. It soon finds its skin too 
strait for it, for this can stretch only to a certain extent, 
and has no power of actual growth as ours has, and the 
horny parts, as the head and feet, cannot even expand, 
being quite rigid. What must be done 1 It splits its 
L 
