Skeleton of a large Water Beetle, as seen from below. B, the head. D D, the prothorax. 



F i^, the mesothorax. H fl^, the metathorax. a a, fore legs, e e, fore wings, ii, middle 



legs. o, hind wings, u u, hind legs, y, antennse. 



CHAPTER I. 



OF THE ORGANS OF SUPPORT, OR SKELETON. 



The Physiology of Insects is the account of how they are 

 made : there are in every animal four essential elements, — 

 matter, motion, sensation, and mind. 



Matter is inert — it does not move by its own powers ; it 

 is tangible — the touch ascertains that it resists : matter in 

 animals has various degrees of consistency ; convenience, 

 however, has suggested its division into solid and fluid. 



