Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 524 ISSECTA* tern, fig. 430). While the labium is usually reduced to a simple plate with two lateral palps (palpi labiales), in the Orlhojttera we can distinguish a proximal piece (submentum), fixed to the throat, from a second piece, bearing the two palps (mentum), at the point of which there is a piece, the tongue (glossa) (fig. 430, e, L. in), and sometimes secondary pieces, the paraylossce, (L. ex). The sub- mentum
Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 524 ISSECTA* tern, fig. 430). While the labium is usually reduced to a simple plate with two lateral palps (palpi labiales), in the Orlhojttera we can distinguish a proximal piece (submentum), fixed to the throat, from a second piece, bearing the two palps (mentum), at the point of which there is a piece, the tongue (glossa) (fig. 430, e, L. in), and sometimes secondary pieces, the paraylossce, (L. ex). The sub- mentum evidently corresponds to the fused basal joints (cardo), the mentum to the fused shafts (stipes), the simple or bifid glossa to the lobus interims, and the paraglossse to the lobus externus of the first maxill?e. Median projections on the internal surface of the upper and lower lips are distinguished as epipkarynx and liypo- pliarynx respectively. The above description refers to insects which gnaw or bite their food. When the food is fluid, the mouth parts, either in whole or part, become so remarkably modi- fied that it required the penetration of Savigny to establish their morphological relations. The biting mouth parts found in the orders of the Coleoptera, the Neuroptera and the Orthoptera are most nearly allied to the mouth parts of the Hym&noptera, which may be described as a licking apparatus (fig. 431). The upper lip and mandibles agree with of the biting apparatus, but the maxillae and la- bium are more or less elongated and modi- fied, to admit of licking and sucking up fluids. Mouth parts adapted for sucking are found in the Lepidoptera, where the first maxillae are united to form a sucking tube, while the other parts are more or less aborted (fig. 432). Finally the piercing mouth parts of the Diptera and Rhynchota also possess a sucking apparatus, which is usually formed of the labium ; but there are also styliform wea- pons, by means of which access is gain
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