ENTOMOLOGY. 123 



a telescope, and can readily be moved in any direc- 

 n. Such a confirmation is well exemplified by the 

 .phylinidae, which elevate and twist about their 

 domen with the utmost facility, and even turn it 

 er the back to push the wings under their short 

 ses,* The whole of the segments are lined in- 

 nally with a soft membrane, which connects 

 3m, and retains them in their places, without im- 

 ding their movements. This membrane becomes 

 >ible when the abdomen is in a distended state, as 

 a gravid female, when the abdomen seems to form 

 >ag, with horny plates arranged in a certain order 

 er its surface. 



An opening for the respiratory organs, which 

 mify through the body, may be observed near the 

 eral margin of each segment. These openings are 

 rrounded with a hard ring, and are called spiracles 

 air-holes, {Stigma, Spiracula.) 

 It has been well observed that each of the three 

 eat divisions of the body is the appointed seat of a 

 ^arate set of organs, all of them alike important in 

 e animal economy. As the head contains the 

 gans of mastication, and the thorax those of mo- 

 on, so the abdomen is the appropriate site of the 

 3nerative organs. These, however, are chiefly in- 

 jrnal, and will be most conveniently considered 

 hen treating of the anatomy of the abdomen. Such 

 sternal appendages, too, as are more or less acces- 

 )ry to the organs alluded to, as well as various others 

 diich, as far as known, have no connection with 



* See Lacord. Introd. I. 447. 



