100 THE ANATOMY OP THE HONEY BEE. 



SO involves the tearing of all the fine muscle fibers and tracheal 

 branches uniting the honey-stomach to the upper end of the ventricu- 

 lus (fig. 45). If, then, the organ itself can not be made to work 

 according to this scheme, it might be supposed that the inner wall of 

 the proventriculus and the tube are evaginated through the stomach- 

 mouth (nn), but the walls of the former certainly appear to be en- 

 tirely too rigid to permit of any such performance as this. Finally, 

 it is not clear how any eversion of the tube could be produced by the 

 proventricular muscles as they exist. 



The various facts and arguments bearing on the origin of the 

 brood food may be summarized as follows: 



1. The brood food itself is a milky-white, finely granular, and 

 gummy paste having a strong acid reaction said to be due to the 

 presence of tartaric acid. 



2. The pharyngeal glands of the head are developed in proportion 

 to the social specialization of the various species of bees; they are 

 always largest in those individuals that feed the brood, and they 

 reach their highest development in the workers of the honey bee. 

 From this it would seem that they are accessory to some special 

 function of the worker. 



3. The contents of the stomach in the workers consist of a dark 

 brown, slimy, or mucilaginous substance in no way resembling the 

 brood food, even when acidulated with tartaric acid. Pollen is 

 present in varying quantity, mostly in the posterior end of the 

 stomach, and shows little or no evidence of digestion. Since the 

 brood food is highly nutritious, it must contain an abundance of 

 nitrogenous food material which is derived only from pollen in the 

 •bee's diet. Therefore it is not clear how the stomach contents can 

 alone form brood food. 



4. The constituents of the food given to the different larvae, at 

 different stages in their growth, and to the adult queens and drones 

 show a constant variation apparently regulated by the workers pro- 

 ducing it. A variation of this sort can not be explained if it is 

 assumed that the brood food is produced by the glands alone. 



5. Powdered charcoal fed to a hive of bees appears after a short 

 time in the brood food in the cells, and this has been urged as proof 

 that the latter is regurgitated " chyle." But it is certainly entirely 

 possible that the charcoal found in the food might have come only 

 from the honey stomach or even from the oesophagus or mouth. 



6. We have Schonfeld's word for the statement that a regurgita- 

 tion of the stomach contents may be artificially induced by irritation 

 of the honey stomach and ventriculus in a freshly dissected bee, but 

 all explanations offered to show how this is mechanically possible 

 in spite of the proventricular valve are unsatisfactory when the 

 actual anatomical structure is taken into consideration. 



