PHYSIOLOGY OF THE BEE. 97 



Much remains to be done to clear up the mysteries 

 still unsolved, and to harmonise the various observa- 

 tions already made respecting the nature and pro- 

 perties of these organs, which, not only in bees, but 

 in many other families of insects, play such an im- 

 portant part in their life-history. 



The Mouth. Passing next to the mouth, we find a 

 somewhat complex structure ; for it consists of many 

 parts, each of which has its ascertained function. 

 We find first, the labrum, or upper lip ; the epipharynx, 

 or valve closing the aperture of the gullet ; the 

 pharynx, or gullet, forming the true mouth, as well 

 as the entrance to the oesophagus, or food-pipe ; 

 the hypopharynx, lying just below the gullet ; the 

 labium, or lower lip ; and the proboscis, or true 

 tongue. These are all single parts ; but there are 

 also pairs of mandibles, or upper jaws, and maxilla, or 

 lower jaws, besides palpi certain jointed, sensiferous 

 organs, whose functions are not well understood, but 

 which are possibly connected with the sensation of 

 taste. 



The labrum, or upper lip, has a vertical motion, 

 and when not in use falls over the organs beneath it ; 

 while it is covered, in its turn, by the mandibles, 

 which are jointed on to the cheeks, and act laterally. 



The pharynx is a cavity lying beneath the 

 epipharynx, and can be closed by the latter, over 

 which the two previously described parts lap, so that 

 the entrance to the oesophagus is trebly protected. 



The labium, or lower lip, is capable of being pushed 

 forward and retracted, and lies, when not in use, 

 within the under cavity of the head. 



On either side are the maxillce, or so-called jaws, 



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