EXTERNAL ANATOMY OF INSECTS. 545 
Scarites belonging to that tribe, the Lamellicorn beetles, 
and the mole-cricket, they are fossorious legs, or proper 
for digging? ; in Mantis, Nepa, and some Diptera, they 
are raptorious, or fitted to seize and dispatch their prey?: 
they are used also by many insects to clean their head, 
eyes, and antennz, &c. For many of these purposes 
they cannot be fit without a structure different from that 
of the other legs, which renders it a matter of as great 
convenience in descriptions to speak of them and their 
parts under different names from those of the legs, as it 
is of the arms of man; on this account it is that I propose 
to give to the fore-leg and its parts the names by which 
-the analogous parts, or what are so esteemed, in the 
human species are distinguished ;—when spoken of in 
common with the other legs, they may still be called the 
forelegs. 
** Alitruncus. Thealitrunk is the posterior segment 
of the trunk, which below bears the four true legs, and 
above the organs for flight or their representatives. In 
treating of this part we may consider its znsertion or ar- 
ticulation, its shape, composition, substance, motions, and 
organs. 
i. With regard to its znsertzon, or articulation with the 
manitrunk and abdomen, it may be observed that it is 
attached to both by its whole circumference by means of 
ligament ; in the Coleoptera, Orthoptera, and Heteropte- 
rous Hemiptera being received by the posterior cavity of 
the prothoraz, the shield of which in these Orders, espe- 
cially the last, almost covers and conceals it; but in the 
* Prate XV. Fic. 5, 6. > Samouelle ¢. v. f. 4. 
VOL, III. 2N 
