WINGED INSECTS. 303 



tmnsient is the state of perfection in every thing 

 that relates to animal existence. When the in- 

 sect has by a slow developement reached this 

 ultimate elaboration of its organs, its life is 

 hastening to a close ; and the period of its perfect 

 state is generally the shortest of its whole ex- 

 istence. 



The history of the successive stages of deve- 

 lopement of insects opens a highly interesting 

 field of philosophical inquiry. For a certain pe- 

 riod of the early life of these animals, the growth 

 of all the parts appears to proceed equably and 

 uniformly : but at subsequent epochs, some parts 

 acquire a great and sudden increase of size, and 

 others that were in a rudimental condition become 

 highly developed, and constitute what appear to 

 be new forms of organs, although their elements 

 were in existence from a much earlier period. 

 The modifications which the harder and more 

 solid structures of insects exhibit in the progress 

 of these changes, are particularly remarkable, as 

 illustrating the principles on which the develope- 

 ment is conducted. The researches of modern 

 entomologists have led to the conclusion that the 

 frame-work, or skeleton of insects, is always 

 formed by the union of a certain determinate 

 number of parts, or elements, originally distinct 

 from one another, but which are variously joined 

 and soldered together in the progress of growth : 

 frequently exhibiting a great disproportion in 



