116 LECTURE IX. 



The last Order of Insects is called Aptera, and 

 comprises Wingless Insects. It consists, according 

 to Linnseus, of the Crab and Lobster tribe, of Spi- 

 ders, Scorpions, Centipedes, Monoculi, Mites, and 

 many other Insects. But, as I have before ob- 

 served, some of the French zoologists have been 

 inclined to dismiss the Crab and Lobster tribe, 

 the Monoculi, &c. from the class of Insects. The 

 Crabs and Lobsters, as is well known, cast their 

 skins annually, the body shrinking before the 

 change, and enabling them easily to draw out 

 their limbs from the shell : the animal being then 

 in a weak and tender state, remains in some quiet 

 retreat till its new shell is completely grown. 

 This genus is excessively numerous, and some of 

 the species are extremely small. The larger ani- 

 mals of the kind, as the larger kind of Crabs 

 for instance, possess the extraordinary power of 

 casting off at pleasure any limb that happens to 

 be accidentally maimed or bruised, instead of 

 waiting for a gradual convalescence : a new limb 

 is soon afterwards formed, which gradually sup- 

 plies the place of that which had been voluntarily 

 cast off. 



The Scorpions, forming the genus Scorpio of 



