ORDER VII. - APTERA. 313 



measure several inches in length, while others are imper- 

 ceptible by the naked eye. All, however, possess the art 

 of inflicting pungent pain; and, where they swarm, it is 

 almost impossible to enjoy quiet by day or rest by night. 



ORDER VII APTERA. 



THE characteristic of animals in this order is, that they 

 are destitute of wings. It comprehends fifteen genera ; 

 in which are included the spider, the acarus, the flea, the 

 louse, the termes or white ant, the scorpion, the crab, 

 and the lobster. 



No general description can embrace subjects so various, 

 and creatures in reality so dissimilar in their nature, 

 though accidentally agreeing in the single circumstance of 

 having no wings. This article shall therefore be dismissed 

 with a few explanatory remarks on that curious subject, 

 the metamorphosis and generation of insects. 



Except the aptera order, all insects are constantly and 

 successively undergoing some transformation. From the 

 egg they become a caterpillar or maggot, then a chrysalis, 

 and lastly a perfect fly. During each of these changes, 

 their appearance differs as much, as if they were distinct 

 productions of nature. Before the insect undergoes the 

 third and last change, it has arrived at its full growth ; 

 when it waits only for the expansion of its wings. Such 

 is the disposition to change in this class of animals, that 

 even the crustaceous insects, such as crabs and lobsters, 

 belonging, and bearing a distant analogy, to the order of 

 aptera, annually cast their shells, as their growth would 

 otherwise be impeded. 



Among insects in general, the same difference of sex 

 exists as in large animals ; and some of them, when they 

 become perfect, seem to be produced for no other purpose 

 than to propagate their kind. Thus the silk- worm, when 



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