54:6 EXTERNAL ANATOMY OF INSECTS. 



throat a . In one instance, Gryllotalpa, this part is a long- 

 piece between the arms, shaped like the human thigh- 

 bone or tibia, being more slender in the middle and 

 widest at the ends, and which is of a much harder sub- 

 stance than the rest of the antepectus, and forms the 

 lower termination of a singular machine which will be- 

 fore long be noticed. In many bugs (Cimicidce), instead 

 of being elevated, the three portions of the sternum are 

 hollowed out into a longitudinal groove, in which the 

 promuscis when unemployed reposes. 



The most conspicuous and remarkable appendages of 

 the manitrunk, are the brachia or arms. I shall not, 

 however, enter into the full consideration of these, as they 

 consist numerically of the same parts, till I treat of the 

 legs in general. Here it will only be necessary to assign 

 my reasons for calling them by a distinct denomination. 

 In this I think I am authorized, not only by the example 

 of Linne, who occasionally found it necessary to do this b , 

 and more particularly by the ancient notion that this 

 pair of organs in insects were not to be reckoned as legs , 

 but likewise from their different position and functions. 

 They are so inserted in the antepectus as to point towards 

 the head, whereas the other two pair point to the anus. 

 With regard to their functions, besides being ambula- 

 tory, and supporting the manitrunk in walking, they are 

 applied to many other purposes independent of that of- 

 fice, — thus they are eminently the scansory or climbing 

 legs in almost all insects ; in most Carabi L., by means 



a Linn. Trans, iv. 53. b Syst. Nat. i. Cancer. Scorpio. 



c Moses, when he describe sinsects as going upon four legs, evi- 

 dently considers the anterior pair as arms ; Bochart does the same. 

 Levit. xi. 20—. Hierozoic. ii. 497. 



