LECTURE IX. 
ns 
The last Order of Insects is called Aptera, and 
comprises Wingless Insects. It consists,, according 
to Linnasus, of the Crab and Lobster tribe, of Spi- 
ders, Scorpions, Centipedes, Monoculi, Mites, and 
many other Insects. But, as I have before ob- 
served3 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 Scurpionsy forming the genus Scorpio of 
