PHYSIOLOGY OF INSECTS. 101 



is almost invariably smaller than either of the 

 preceding: in many tribes it is so exceedingly 

 slender and thread-like, that the insect is divided 

 into two large incrassated masses. 



332. From this appearance, the terms entomos, 

 insectum, insecte } insect, &c. have arisen : the 

 ichneumon, the common wasp, the honey-bee, the 

 butterfly, the house-fly, are all familiar illus- 

 trations of this, and may be termed pedunculated 

 insects : in these instances, the podeon is so arti- 

 culated as to possess great freedom of motion ; but 

 in beetles, locusts, &c., in which it is not materially 

 less than the propodeon it possesses but little 

 power of motion. 



333. The seventh segment (metapodeon) in the 

 pedunculated insects, is very small at its union 

 with the podeon, but very large at its union with 

 the eighth segment : in other insects it is of 

 uniform size. 



334. The eighth segment (octoon) in the pedun- 

 culated insects, is the largest segment, with the 

 exception of the mesothorax ; in some of the 

 wasps and the smaller ichneumons, it is larger 

 than the whole of the five following segments, 

 which are not unfrequently concealed within it. 



335. The ninth segment (ennaton), tenth seg- 

 ment (decaton), and eleventh segment (protelum), 

 are still smaller ; uniformly decreasing in size, and 

 often retractile each within the one preceding it. 



336. The twelfth segment (paratelum) is still 



