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MANUAL OF ZOOLOGY. 



form of bristles, by which powerful leaps can be effected, as is 

 seen in the Springtails (Podurce). In some insects (as the 

 Mole-cricket and Cockroach), the 9th or roth abdominal seg- 

 ment carries jointed antenniform appendages, which, though 

 perhaps partially or even primarily generative in function, are 

 certainly organs of sense, being connected with smell or 

 hearing. 



The organs about the mouth in Insects are collectively 

 termed the "trophi," or "instrumenta cibaria." Two principal 

 types require consideration namely, the masticatory and the 

 suctorial both types being sometimes modified, and occasion- 

 ally combined. 



In the Masticatory Insects, such as the Beetles (fig. 105, i), 



Fig. 105. Organs of the mouth in Insects, i. Trophi of a masticating Insect (Beetle): 

 a Labriim or upper lip ; b Mandibles; c Maxillae with their palpi; d Labium or 

 lower lip with its palpi. 2. Mouth of a Butterfly: o Eye ; f Base of antennae : g 

 Labial palp; h Spiral trunk or "antlia." 3. Mouth of a Hemipterous Insect (Nepa 

 cinerea)'. /Labium; in Maxillae; n Mandibles. 



the trophi consist of the following parts, from before back- 

 wards : (i.) An upper lip, or "labrum," attached below the 

 front of the head. (2.) A pair of biting-jaws, or "mandibles." 

 (3.) A pair of chewing-jaws, or "maxillae," provided with one 

 or more pairs' of "maxillary palps," or sensory and tactile 

 filaments. (4.) A lower lip, or "labium," composed of a 

 second coalescent pair of maxillae, and also bearing a pair of 

 palpi, the " labial palps." The primitive form of the labium, 

 that, namely, of a second pair of maxillae, is more or less per- 

 fectly retained by the Orthoptera and some of the Neuroptera. 

 The lower or basal portion of the labium is called the "men- 

 turn " or chin, whilst the upper portion is more flexible, and is 

 termed the " ligula." The upper portion of the ligula is often 



