24 EXTERNAL ANATOMY OF INSECTS. 



examine Ci^chrus. The middle lobe of the lip seems to be 

 completely cut away ; and the feeler-bearer appears in its 

 place, with a pair of closely-approximating feelers rising from 

 its summit. Turn the other surface of the lip, and apply 

 a good lens : you will find the trilobed ligula, minute indeed, 

 but beautifully distinct ; the lateral lobes being rather longer 

 than the central lobe, and termed by Latreille paiaglossa-. 

 Blethisa and Nebiia present a very similar structure, except 

 in the central lobe of the ligula, which in these is large and 

 somewhat rounded. In Helobia the central lobe has a central 

 tooth. In the Harpalida; and Scaritido!, the ligula is 

 generally more produced ; and the feeler-bearer and feelers 

 are carried with it. In JJcinus, the lip and its appendages 

 are similar to those of Cychrus. You will find the same 

 similarity in the feeler-jaw and its appendages. In the Dy- 

 tiscites no great difference appears ; the lateral lobes of the 

 ligula are however mostly obsolete. In the HijdrophiUtes 

 the lip is less indented than in predaceous beetles ; the ligula 

 is frequently bilobed, and the feelers appear to lose one 

 joint by the second being received into a cup formed by the 

 first. In Hydrous, the feeler-bearer appears obsolete ; and 

 the insertion of the feelers behind the lip actually swells out 

 the portions of its margin, behind which it enters. In Parnus, 

 supposed to be nearly related to Tlydroils, the feeler-bearer 

 and feelers project far beyond the lip. In Tetratoma, and Cis, 

 the feeler-bearer is raised, but the ligula is concealed. In 

 Leiodes all the four parts are distinctly developed. In Trox, 

 the insertion is peculiarly prominent; and still more remarkably 

 so in Acant/iocerus." In the vast order, Cwculionites, I find 

 the feeler-bearer very prominent and elongate ; yet the ligula 

 is mostly obsolete or concealed. In Curtis's figure of Mono- 

 nyclms there appears to be a distinct ligula; — I have never 

 investigated the mouth of this genus. It seems a general 

 character of the order, that the feeler-bearer should be promi- 

 nent and elongate, the feelers approximate, placed at its 

 summit, and occupying the usual situation of the ligula. In 

 the Cerambicitcs, the four parts of the lip are very distinct : 

 in Saperda, and Hematicherus, particularly so. The remaining 



" Mentum quasi e dupHci parte formatum, alia apiculi cordata ad basin, 

 truncata, carinata, margine antico emarginato, lateribus rotundatis, elevatis ; 

 altera prioris stipite transversa, concava, margine antico recto, lineari. — MacLeay. 



