8 MODERN CLASSIFICATION OF INSECTS. 



The Organs of the Moxith (upon tlie variations in which Fabricius 

 constructed his system) are, notwithstanding all their variety of form, 

 reducible to one type of structure. They consist of six principal 

 organs, of which four are lateral and disposed in pairs : the two others 

 are opposed in the opposite direction: thus, :':, filling up the space 

 left by the two other pairs above and beneath. The upper single 

 piece is the upper lip (labrum) : the upper lateral pair of organs are 

 the mandibles or upper jaws; the lower lateral pieces are the max- 

 illae, or lower jaws, and the under single piece is the under lip. The 

 three lower organs are furnished with articulated appendages (jtaJpi). 

 The first principal variation in the structure of the mouth originates 

 in the mode of action of the various organs. Thus, when the lateral 

 pieces are short, inserted at a distance apart, and have a horizontal 

 motion, the action is that of biting ; when, on the other hand, the 

 lateral pieces are elongated, originating near together, and having a 

 longitudinal motion (by means of strong and elongated muscles at their 

 base), the action ia that of sucking ; the ascension of fluids in the 

 latter case being produced by the gradual approximation of the pieces 

 of the mouth (^Latr. Cows, d Entomol. p. 206.), which thus form a 

 siphon or haustellum. The insects having the former action are termed 

 Broyeurs by the French, and Mandibulata by the English, and the 

 latter Su9eurs, or Haustellata; but as these, terms are liable to ob- 

 jection (the insects composing the latter group possessing mandibles, 

 although in an altered form), it would be convenient to employ some 

 other names. The terms Dacnostomata and Antliostomata express 

 the properties of the two groups, without involving the contradiction 

 suggested by the terms ordinarily in use. 



In the Biting Insects, the upper lip is generally a simple and flat- 

 tened plate closing the mouth above ; the mandibles are generally 

 horny, and more or less toothed (the teeth being, howevei", portions 

 of the jaw itself), serving for gnawing in pieces the particles of food ; 

 the maxillae are more complicated, being furnished at the side with 

 an articulated appendage like a short antenna, but of which the 

 number of joints is never more than six. The maxilla itself is termi- 

 nated by two lobes, the exterior of which is sometimes articulated, 

 representing an internal palpus as in Carabus, sometimes formed into a 

 helmet-like appendage ( Galea), protecting the inner lobe as in Locusta, 

 and sometimes soldered to the inner lobe. The lower lip is still more 

 complicated; its base is a horny plate {inentum^ or the labium of 



