v.] METAMORPHOSES OF INSECTS. 81 



ence to its immediate wants, rather than to its final 

 form. 



3. That metamorphoses may therefore be divided 

 into two kinds, developmental and adaptional or 

 adaptive. 



4. That the apparent abruptness of the changes 

 which insects undergo, arises in great measure from 

 the hardness of their skin, which admits of no gradual 

 alteration of form, and which is itself necessary in 

 order to afford sufficient support to the muscles. 



5. The immobility of the pupa or chrysalis depends 

 on the rapidity of the changes going on in it. 



6. Although the majority of insects go through 

 three well-marked stages after leaving the egg, still a 

 large number arrive at maturity through* a greater or 

 smaller number of slight changes. 



7. When the external organs arrive at this final 

 form before the organs of reproduction are matured, 

 these changes are known as metamorphoses; when, 

 on the contrary, the organs of reproduction are 

 functionally perfect before the external organs, or 

 when the creature has the power of budding, then the 

 phenomenon is known as alternation of generations. 



G 



