INSECTS. 85 



the solid trunk of an oak winged and capable of flight so rapid 

 as to render escape hopeless ; what could resist such destroyers, 

 or how could the world support their ravages ? 



Insects may, therefore, be regarded in the light of engines, so 

 perfectly adapted to the work intrusted to them, that to increase 

 or diminish their size would be to unfit them for the duties for 

 which they are specially constructed, and, as a necessary conse- 

 quence, no insect iti its ringed condition can be permitted to grow ; 

 its growth must be effected under other circumstances, and gene- 

 rally under a form quite different from that which it presents in 



FIG. 77. METAMORPHOSES OF BUTTERFLY. 



its perfect state. Hence arises the necessity for the Metamor- 

 phosis of Insects. 



Most insects in the course of their lives are subject to very great 

 changes of form, attended by equally remarkable alterations in 

 their habits and propensities. These transformations or mctamor- 

 pJioses, as they are called, quite as strange as any we read of in 

 Ovid, might cause the same insect, at different ages, to be mis- 

 taken for three different animals. For example, a caterpillar, 

 after feeding upon leaves till it is fully grown, retires into some 

 place of concealment, throws off its caterpillar skin, and presents 

 itself in an entirely different shape, wherein it has no power of 

 moving about nor of taking food. In this, its second or chrysalis 



