OF THE SKELETON. 145 



segments which succeed it. In many tribes, as the Sphex, 

 it is so exceedingly slender and thread-like, that the insect 

 is divided into two large incrassated mass- 

 es, vulgarly known by the name of thorax 

 and abdomen : the upper or thoracical mass 

 is composed of the four segments already 

 described, the alternate ones being shaded 

 in the figure in order more distinctly to 

 show the limits of each. From this ap- 

 pearance the terms entomos, insectum, in- 

 secte, insect, &c., have arisen. The Sphex 

 figured in the margin, the Ichneumon at z 

 page 8, the breeze fly at page 25, the com- 

 mon wasp, honey-bee, butterfly, house fly, and multitudes 

 of other insects, are familiar illustrations of this insected 

 appearance, and may be aptly designated pedunculated 

 insects. In all these instances the podeon is so articulated 

 to the propodeon as to possess great freedom of motion ; 

 in beetles, the Phasma, Mantis, locust, &c., in which it is 

 not materially less than the propodeon, it possesses on the 

 contrary, but little power of motion. 



The abdominal segments, forming the second incrassated 

 mass, possess few characters of interest comparable to that 

 of those which precede. The seventh segment, or meta- 

 podeon, in pedunculated insects is very small at its union 

 with the podeon, and very large at its union with the fol- 

 lowing segment; in other insects it is of uniform size. 

 The eighth segment, octoon, in the pedunculated insects is 

 the largest segment, with the exception of the mesothorax; 

 in some of the wasps, and the smaller Ichneumones, it is 

 larger than the whole of the five following segments, which 

 are not unfrequently concealed within it. The ninth seg- 

 ment, ennaton, tenth segment, decaton, and eleventh seg 

 ment, protelnm, gradually decrease in size, and are 



L 



