212 NATURAL IHEOLOaY. 



or beetle, furnish an example of this kind. The true wing 

 of the animal is a light, transparent membrane, finer than 

 the finest gauze, and not unlike it. It is also, when expand- 

 ed, in proportion to the size of the animal, very large. In 

 order to protect this delicate structure, and perhaps, also, to 

 •preserve it in a due state of suppleness and humidity, a 

 strong, hard case is given to it in the shape of the horny 

 wing which we call the elytron. When the animal is at 

 rest, the gauze wings lie folded up under this impenetrable 

 shield. When the beetle prepares for flying, he raises the 

 integument, and spreads out his thin membrane to the air.* 

 And it cannot be observed without admiration, what a tissue 

 of cordage, that is, of muscular tendons, must run in various 

 and complicated, but determinate directions, along this fine 

 surface, in order to enable the animal either to gather it up 

 into a certain precise form, whenever it desires to place its 

 wings under the shelter v\4iich nature has given to them, 

 or to expand again their folds when wanted for action 



In some insects, the elytra cover the whole body; in oth 

 ers, half; in others, only a small part of it ; but in all, they 

 completely hide and cover the true wings. Also, 



Many or most of the beetle species lodge in holes in the 

 earth, environed by hard, rough substances, and have fre- 

 quently to squeeze their way through narrow passages ; in 

 which situation, wings so tender, and so large, could scarce- 

 ly have escaped injury, without both a firm covering to de- 

 fend them, and the capacity of collecting themselves up un- 

 der its protection. 



11. Another contrivance, equally mechanical and equally 

 clear, is the aivl, or borer, fixed at the tails of various species 

 of files ; and with which they pierce, in some cases, plants ; 

 in others, wood ; in others, the skin and flesh of animals ; in 

 others, the coat of the chrysalis of insects of a different species 

 from their own ; and in others, even lime, mortar, and stone 

 1 need not add, that having pierced tho substance, they do- 

 * Plate V.. Ftg. 6. a, a, the elytra; t, 6, the true winsfs. 



