254 ANATOMY. 



preceding joint, the latter from the exterior, and both insert them- 

 selves at the corresponding parts of the basal aperture of the joint which 

 they move. 



172. 



MUSCLES OF THE LIPS. 



The upper lip, or labrum, has in Mdolonlha but one kind of muscle, 

 namely, the flexor or bender, which originates on each side from the 

 brow, close to the eyes, and runs down to the extreme angle of the 

 labrum. In Locusta, I have distinctly observed two different muscles ; 

 both were flat, resembling bands, and originated from the forehead, 

 the anterior one, or abductor of the labrum, originated between the. 

 eyes, and inserted itself upon the inner surface of the exterior wall of 

 the labrum ; the second, or adductor of the labrum, originated above 

 the former, at the boundary between the forehead and vertex, and ran 

 separated from it as far as the apex of the labrum, leaning against the 

 membrane of the soft palate, and supporting it. 



The labium, like the maxillae, being of a more complicated struc- 

 ture, receives several muscles. 



The adductor of the labium originates from the most anterior edge 

 of the skeleton of the head; it has a broad basis, and runs pyramidally 

 to the mentum, joining it in front of the articulation of the palpi. In 

 the Coleoptera there are two adductors, one on each side of the men- 

 tum ; in Locusta I found but one central one. 



In front of it, or between them when there are two adductors to the 

 labium, the muscles of the tongue originate, which are two, likewise 

 short, pyramidal muscles inserted at the lower side of the tongue, and 

 connect this with the labium : 1 call them the reins of the tongue. In 

 Locusta I found but one muscle of the tongue, resembling that of the 

 labium in its broad flat form, which originated in front of the latter, 

 from the tentorium, and passed to the posterior wall of the tongue. 

 To the anterior wall, or the soft membrane clothing the tongue, on the 

 contrary, another muscle passed, which I call the flexor of the tongue, 

 and which, running likewise closely to the membrane of the tongue 

 and of the palate, originated with a broad base from the anterior 

 boundary of the tentorium. 



The first joint of the labial palpus has its flexor and extensor; the 



