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to which some of the feet are affixed. The upper part is the thorax, 
behind which is the scutellum, or escutcheon, mostly of a triangu- 
lar form, and occupying a part on the margin of each elytron, or 
upper wing. The under part is the sternum, or breast. 
The thorax is the upper part of the breast between the head and 
wing-cases, and in form various. If the sides are armed with points, 
it is called dentatus ; when they are placed on the back, spinosus ; 
and if the margin is laterally dilated, marginatus. 
The abdomen is mostly distinct from the thorax, and forms the 
posterior part of the insect: it contains, the stomach, intestines, 
and viscera, and is composed of five annular rings, or segments, on 
the sides of which, are the spiracula, or pores, which serve for re- 
spiration ; the upper side of the abdomen is called the tergum, or 
back ; and the under part, the venter, or belly, at the extremity 
of which is the anus. 
At the end of the abdomen is the tail, which in many objects has 
two appendices, in some three, and in others none ; this part 
is either simple, or armed with a forceps, sharp point, or sting, 
which again, is either smooth or serrated. 
Pedes, or legs, are composed of the following divisions, viz. 
femora, or thighs, joints next the body: tibiæ, or shanks, the se- 
cond joints ; the tarsi, or feet, form the third set, and are composed 
of an indefinite number of articulations, at the extremity of which 
are the ungues, called claws, or nails ; the hind feet are calculated 
for different motions, as swimming, leaping, or running. 
Alæ, wings, are membraneous, and undivided ; some insects 
have two, others four, which are either, 
