GRAMMAR OF ENTOMOLOGY. 



which an insect's life is passed, and many of 

 which we have recorded in the preceding Book, 

 it is essential that this bony covering should be 

 in some way jointed, otherwise constant difficulty 

 must occur. 



317. The body, therefore, which is very long 

 in proportion to its breadth, is divided into thir- 

 teen rings or segments (segmenta), the interstices 

 between these being filled by a softer and more 

 flexible portion of the same skin, which, in its 

 indurated state, forms the segments. 



318. This alternation of flexible and inflexible 

 portions of skin, allows not merely a free motion 

 to the right or left, upwards or downwards, but 

 of great increase or decrease of length at the 

 pleasure of the insect. 



319. Contraction is readily performed by the 

 rings being drawn one within another ; and elon- 

 gation, by extending and separating the rings : 

 their action is in some degree represented by 

 the sliding of the tubes of a telescope. The body 

 of the common wasp will illustrate this contracting 

 and elongating power. 



320. With the exception of the first, which is 

 the head in all insects, the segments have no 

 English names ; the Latin ones are, therefore, 

 universally used ; and this is preferable to burthen- 

 ing the mind with two names for the same part. 



321. The first segment is the head (capuf) ; it 

 consists of a skull, in which are situated two 



