54 PARTIAL ORISMOLOGY. 



with the margin of the throat (the sternum capitale of some entomolo- 

 gists), and forms from beneath the inferior covering of the mouth. 



The TONGUE (ligula, Fab.; lingua, Kirby and Spence, PI. IV. f. 4. B) 

 reposes internally upon the chin. It is, in general, a membranaceous 

 or more or less fleshy organ, which frequently protrudes beyond the 

 anterior margin of the chin, in which case its exterior inferior side 

 is horny; this horny part is then called TONGUE-BONE (os hyoideum), 

 or FULCRUM (fulcrum). The LABIAL PALPI (palpi labiates^) are close 

 to this, and indeed frequently inserted upon it. The upper fleshy part, 

 the true tongue, is frequently simple, and visibly separated from the 

 chin (PL IV. f. 5), as in the Orthoptera and Xenroptera; in other cases 

 it is divided, and very closely connected with that organ (Coleoptera). 

 In the wasps it is separated into several (three or four) lobes. In the 

 bees it projects as a long cylindrical, frequently pubescent, retractile 

 filament : in some of the fossores (Scolia} this filament is divided into 

 three. 



Illiger and Latreille call the tongues of insects with a masticating 

 mouth the labium ; in Fabricius, on the contrary, the labium is some- 

 times our mentum, and sometimes, when the chin and tongue are not 

 distinctly separated, the whole inferior flap of the mouth. 



The already frequently mentioned FEELERS (palpi) are the auxiliary 

 organs of a masticating mouth ; they are many -jointed and but seldom 

 simple appendages, inserted upon the maxillae and labium. Those upon 

 the maxillae, the MAXILLARY FEELERS (palpi muxillares, PI. III. f. 16, 

 A), generally originate from where the scale is connected with the 

 external lobe, and are united to it by a very supple hinge. The 

 LABIAL FEELERS (palpi labiales, PI. IV. f. 3. c, c) are placed late- 

 rally upon the labium, close to the tongue, more or less approximate to 

 the part where it projects beyond the chin (Cerambycina, Carabodea) ; 

 in other instances tbey are decidedly inserted in the margin of the chin 

 (Libellula, Lamellicornia}. The number of the joints of these organs, 

 whose length, form, and relation to each other, is very various, never 

 exceeds six ; and, in general, the labial palpi have fewer joints than 

 the maxillary. We have already spoken of a third two-jointed pair of 

 feelers the INTERNAL .MAXILLARY PALPI (palpi maxillares interni, 

 PI. III. f. 17, 5, and PI. IV. f. 10, 5), which are found only in the tiger 

 beetles (Cicindelacea), the Carabodea, and the water beetles, and which 

 are analogous to the HELMET (zalca) of the Orthoptera^ 



