20 PHYSIOLOGY OF THE HOXEY-BEB. 



oesophagus (oe) the gullet, through which the food goes into 

 the stomach. 



As we have already seen, the canals of the upper glands 

 open on each side of the mouth, and discharge their product 

 into it at will. 



45. The chin or mentum {mi) is not literally a part of 

 the mouth. It can move forward and backward, and supports 

 several pieces, among which is the tongue, or proboscis, cr 

 ligula (Z). The tongue is not an extension of the chin, but 

 has its root in it, and can only be partly drawn back into it, 

 its extremity, when at rest, being folded back under the chin. 



46. There are, on each side of the tongue, the labial palpi 

 or feelers* (h, fig. 12, and Ip, tig. 7), which are fastened to 

 the chin by hinged joints. They are composed of four pieces 

 each, the first two of which are broad, and the other two small 

 and thin, and provided with sensitive hairs of a very fine 

 fabric. Outside of the palpi are the maxilte {c, fig. 12, and 

 mx, fig. 7) which in some insects ha\'e the fmiction of jaws, 

 but which, in the bee, only serve, with the palpi, to enfold 

 the tongue in a sort of tube, formed and opened at the will of 

 the insect, and which, by a certain muscular motion, as also 

 by the ability of the tongue to move up and down in this 

 tube, force the food up into the mouth. 



47. The tongue is covered ^^'ith hairs, which are of graded 

 sizes, so that those nearest the tip or bouton are thin and 

 flexible. It — the tongue — is grooved like a trough, the edges 

 of which can also unite to form a tube, with perfect joints. 

 It is easily understood that if the tongue were a tube, the 

 pollen grains when conveyed through it would obstruct it, 

 especially when daubed with vei-y thick honey. 



48. "A most beautiful adaptation here becomes evident. 

 Nectar gathered from blosaoms needs conversion into honey. 

 Its cane sugar must be changed into grape sugar, and this is 

 accomplished by the admixture of the salivary secretions of 

 Systems Nos. 2 and 3 (sd, 2, 3, fig. 7), either one or both. The 

 tongue is drawn into the mentum by the shortening of the re- 

 Organs of taste according to Leydig and Jobert. 



