INSECTS : THEIR MOUTHS 107 



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 follow- 

 ing organs: 1, the upper lip (Jabrum)', 2, the mandibles' 3, 

 the maxillce; with a, the maxillary palpi; 4, the lower lip 

 (labium), comprising ft, the tongue, y, tne labial palpi, d, the 

 chin (mentum). 



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 recognize them. The 

 under jaws (maxillce) 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 

 constituent parts: the thick opaque chin, at its basal end; 

 then the two labial palpi, each consisting of four joints, of 

 which the two terminal ones are minute, while the two 

 basal are large and greatly lengthened so as to resemble 

 in appearance the maxillce, whose function they imitate 

 also; for the pair of palpi when closed form an inner 

 sheath for the tongue (ligula). Finally you see this or- 

 gan, which is the most curiously developed and modified 

 of all; for it is drawn out to a long slender cylindrical 

 tube, formed of a multitude of close- set rings, and covered 



