402 THE LIFE OF AN INSECT. 



space of time. It has also been found, that when the 

 bodies of insects are covered with oil or grease, so 

 as to stop up their breathing pores, they soon 

 expire. It has been proved by, carefully con- 

 ducted experiments performed by Mr. Ellis, M. 

 Sorg, and other observers, that on placing flies in 

 a measured quantity of atmospheric air, at the end 

 of a day or two almost the whole amount of the 

 oxygen of the air had disappeared, and the same 

 amount of carbonic acid had appeared in the cham- 

 ber in which the insects were confined. We need 

 not, however, after all that has been said on the 

 subject of the respiration of insects in their va- 

 rious stages, enter into any further proofs that 

 insects breathe not less perfectly in their imago 

 condition than in any of the preceding states; 

 in fact, they perform this function far more pro- 

 minently in this their last state than in any of the 

 foregoing. It will also be unnecessary to enter 

 into a consideration of the minute particulars con- 

 nected with this subject, as several of these have 

 been previously glanced at.* 



The air enters the body of the insect at the 

 spiracles, or breathing-pores, which are arranged 

 * See p. 160. 



