146 Beekeeping 



where the ventriculus and small intestine join, the Mal- 

 pighian tubes (Mai) empty into the alimentary canal. 

 The small intestine is coiled and finally empties into the 

 rectal ampulla (Rect, rectum or large intestine). The inner 

 epithelium of the rectum is thrown into six longitudinal 

 folds, the so-called rectal glands (Fig. 77, RGl) of unknown 

 function. It is usually believed that they increase the 

 absorbing surface but, since they are covered on the inner 

 surface with chitin, this explanation seems improbable. 

 The rectal ampulla is capable of considerable expansion 

 and normally retains the feces when bees are confined to 

 the hive, as in winter. It is supposed that most of the 

 absorption of food takes place in the hind-intestine. Peter- 

 sen advances the fantastic theory that the rectal glands 

 are the source of the hive odor. 



The food of bees which must be acted upon by the various 

 digestive juices to be prepared for absorption have their 

 origin in the nectar and pollen collected from flowers. The 

 chief food is honey, which consists largely of invert sugar. 

 This name is given to a mixture of two sugars, levulose and 

 dextrose, which by various means can be made from sucrose 

 (cane sugar). In the higher animals, these sugars are ca- 

 pable of absorption without further change, and this is pre- 

 sumably true of bees also. The sugar in nectar is probably 

 sucrose with some invert sugar. The preparation of this 

 material for absorption therefore begins with the ripening 

 of nectar into honey. As explained earlier (p. 85), this is 

 by the action of an enzyme and, according to Petersen, 

 such an enzyme was extracted from the head of the bee by 

 Erlenmeyer and by v. Planta, presumably from the salivary 

 glands. The absorption of sugars probably occurs in the 

 ventriculus and any water in the honey which is not needed 

 is ejected. The process of such an ejection is not clear. 

 It is also stated by Petersen that the bee produces a diastatic 

 ferment by which the digestion of starch is possible, but he 

 was never able to prove from experiments that starch is 

 changed into dextrin, maltose or dextrose in the honey- 



