INSECTS : THEIR BREATHING ORGANS. 



95 



This, I say, is the breathing system, or a large portion 

 of it. These pipes receive the air from without through 

 trap-doors which we will examine presently, and convey 

 it to the most distant parts of the body. In ourselves 

 the air is inhaled into a great central reservoir — the 

 lungs ; and the blood dispersed through every part is 

 brought to this reservoir to be oxygenated. In insects 

 it is the blood that is collected into a great central 

 reservoir, and the air is distributed by a minutely 

 divided system of vessels over the blood-reservoir. 



The trachece or air-pipes have a silvery white appear- 



WS^W) 



AIE-PIPE OF FLY. 



ance by reflected light ; but if we use transmitted light 

 and put on a high power, we discern a wonderful 

 structure, which I will describe in the eloquent language 

 of Professor Rymer Jones, and you shall estimate its 

 truth as you examine the object : — 



" There is one elegant arrangement connected with the 

 breathing-tubes of an insect specially worthy of admira- 

 tion; and perhaps in the whole range of animal mechanics 

 it would be difficult to point out an example of more 

 exquisite mechanism, whether we consider the object of 

 the contrivance or the remarkable beauty of the structure 



