80 NATURAL ARRANGEMENT OF INSECTS. 



although of an imperfect kind. Now, these belong to 

 two very different groups of annulose animals. In 

 the one, composing the apterous division of Linnseus, 

 there is no appearance of wings : these are his complete 

 pupae. The rest belong to the Ptilota, or winged group, 

 and resemble the perfect insect in every thing but pos- 

 sessing wings, the rudiments of which only appear : 

 these latter are called by some writers semi-complete 

 pupae ; and this name may be retained, because it im- 

 plies an intermediate state of metamorphosis, between 

 the imperfect transformation of an apterous insect, and 

 the perfect or complete one of a butterfly. The period 

 during which insects remain in this state depends upon 

 the species ; some quit it in a few hours, others after 

 some months, while not a few continue in it one or 

 even two years. 



(70.) Let us now look to the third and last state 

 of an insect. We have traced this singular little being 

 through the two preparatory stages of his existence : 

 in the first, he is an inhabitant of the earth, in the 

 second of the grave, and in the third he becomes a 

 denizen of the air. Such, at least, is the life of those 

 perfect, or winged, insects, which are typical of the grand 

 division of animals now before us. The connection 

 between these, and apterous or wingless tribes, is ren- 

 dered gradual by the intervention of the dipterous flies, 

 where the organs of flight are but two ; whereas, in the 

 perfect Ptilota, the wings are almost universally four. 

 When an insect assumes its adult or perfect state, 

 Linnseus termed it an imago. " because, having laid 

 aside its mask, and cast off its swaddling bands, being 

 no longer disguised or confined, or in any respect im- 

 perfect, it is now become a true representative or image, 

 of its species, and is qualified to fulfil the laws of 

 nature in perpetuating its kind. As the power of flying 

 constitutes the perfection of true insects, we accordingly 

 find this in its highest state of developement in the lepi- 

 dopterous order, where the wings are the largest, and 

 the most adapted for rapidity of flight. From this 



