INSECTS : THEIE MOUTHS. 163 



Between the tongue and the biting jaws, or man- 

 dibles, we see a pair of organs similar to these latter, 

 but smaller, less solid and more curved. These are the 

 under or secondary jaws, maxilloe, the use of which is 

 to hold the food, while the biting jaws work on it, and 

 to convey it when masticated to the back of the mouth. 

 Their whole inner edge is set with short stiff bristles, 

 which towards the tips of the jaws become spines. 

 Near the base of these jaws, on the outer edge, are 

 jointed two pairs more of palpi, one pair to each jaw ; 

 of which the exterior is much stouter and longer than 

 the interior. Thus this beetle has three pairs of these 

 many-jointed organs, the labial, and the two pairs of 

 maxillary palpi. 



Now, in this form of mouth, which has been called 

 a perfect or complete mouth — that is, one in which 

 all the constituent parts can be well made out, we 

 find the following organs : — 1. the upper lip {lahruni) ; 

 2. the onandihles / 3. the maxillcB / with a. the Tnax- 

 illary palpi j 4. the lower lip {lahium), comprising 

 /8. the tongue, x. the laMal palpi, B. the chin {men- 

 tum). 



I now exhibit to you the head of the Honey-bee. 

 The front is occupied by an upper lip, and a pair of 

 biting jaws {mandibles), which do not greatly differ 

 from the same parts in a beetle. The jaws, however, 

 are more hatchet-shaped, or rather like the hoof of a 

 horse, supposing the soles to be the opposing surfaces. 

 The other organs are greatly modified, so that you 

 would scarcely recognise them. The under jaws (jnax- 

 illce) are greatly lengthened, and the two, when placed 

 in contact, form a kind of imperfect tube, or sheath. 

 Within these is the lower lip, divided into its constit- 



