96 



INSECTS 



divided mentum, and closes the mouth beneath or behind, 

 according as the position of the head varies. In most Insects 

 the labium appears very different from the maxilla, but in many 

 cases several of the parts corresponding to those of the maxilla 

 can be clearly traced in the labium. 



The mentum is an undivided, frequently very hard, piece, 

 continuous with either the submentum or the gula, and anterior 

 to this are placed the other parts, viz. 

 the labial palpi and their supports, the 

 palpigers ; beyond and between these 

 exists a central piece (Fig. 52, B, e), 

 about whose name some difference of 

 opinion prevails, but which may be called 

 the ligula (languette of French authors), 

 and on each side of this is a paraglossa. 

 In the Orthoptera the single median 

 piece — the ligula of Coleopterists — is 

 represented by two divided parts. In 

 some Insects (many Coleoptera) there is 

 interposed between the mentum and the 

 palpigers a piece called the hypoglottis 

 (Fig. 52, B, I)). It is not so well ascer- 

 tained as it should be, tliat the pieces of 

 the lower lip bearing the same names in 

 different Orders are in all cases really 

 homologous, and comparison suggests that 

 the hypoglottis of Coleoptera may pos- 

 sibly represent the piece corresponding 

 to the mentum of Orthopterists, the so- 



FiG. 52.— Maxilla and lower 

 lip of Coleoptera. A, Ma.x- 

 illa of Passalus : a, cardo ; 

 b, stipes ; c, palpiger ; d, 

 palpus ; e, inner or infe 



outer or superior lobe or 

 galea : B, Labium of Har- 

 'palus caliginosus : «, men- 

 tum ; 6, hypoglottis ; 

 palpiger (support of the 

 labial palp) ; d, palp ; e, 

 ligula ; /, paraglossa. 



rior lobe or lacinia ; /, Called uientum of beetles being in that 

 case the submentum of Orthopterists. 



There is another part of the mouth 

 to which we may call special atten- 

 tion, as it has recently attracted more 

 attention than it formerly did; it is a 

 membranous IoIdc in the interior of the mouth, very conspicuous 

 in Orthoptera, and called tlie tongue, lingua, or hypopharynx ; 

 it reposes, in the interior of the mouth (Fig. 51, o), on the 

 middle parts of the front of the labium; it is probably not 

 entirely lost in Coleoptera, but enters into the composition of the 



