. The Cambridge natural history. Zoology. 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 (F

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. The Cambridge natural history. Zoology. 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

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