THE ALIMENTAKY CANAL AND ITS GLANDS. 93 



of all the parts of the alimentary canal, are alkaline. Hence, it 

 seems very logical to suppose that if the brood food comes from the 

 stomach, its acid constituent is furnished by the glands in the head. 

 But the difference between the brood food found in the cells and the 

 contents of the ventriculus is so great that it would seem as if a very 

 substantial addition of something more than a mere preservative acid 

 must be made to the latter. 



The brood food given to the queen larvae, known as royal jelly, is a 

 gummy paste of a milky-white color when fresh, but when taken out 

 of the cell it soon acquires a darker tone with a yellowish tint. Under 

 the microscope it appears to be a homogeneous, very minutely granu- 

 lar mass. It is very acrid and jDungent to the taste, and must be 

 strongly acid. Samples examined by the writer taken from cells 

 containing queen larvae two and four days old contained a number of 

 fresh undigested pollen grains but no bits of hairs such as occur in 

 the stomach. 



The possible ventricular origin of a part of the brood food and its 

 regurgitation will be further discussed when we treat of the stomach 

 (page 98). The writer does not advocate any personal view regard- 

 ing the origin of this larval food — the fact is, there is not enough 

 known about it to enable one to formulate any opinion worth while. 

 We know only that the whitish paste comes out of the mouths of the 

 workers, but we know nothing of where it is made or of how it is 

 made. Hence we can but await the evidence of further investigation. 



The brood food is fed to the larvae by the workers and is produced 

 in greatest abundance by the younger individuals. The larvae of the 

 queens are said to receive nothing but pure royal jelly throughout 

 their entire developmental period, while the larvae of the drones and 

 the workers are given the pure product only during the first three 

 days of their life. From the beginning of the fourth day on, honey 

 is said to be mixed with the diet of the drones and workers and, in 

 the case of the former, undigested pollen also. Moreover, the adult 

 queens and the drones receive a certain amount of prepared food 

 throughout their lives ; if they do not get it they become weak. While 

 they can feed themselves with honey they apparently can not eat 

 pollen, and consequently are not able to obtain the proteid element of 

 diet unless fed this in a predigested condition by the workers. Dur- 

 ing egg-laying activity the queen especially demands this food, and 

 by furnishing or withholding it the workers probably have the power 

 of stimulating or inhibiting her production of eggs. Arnhart (1906) 

 says that the workers feed it to weak or starved members of their own 

 class, the material being accumulated upon the upper surface of the 

 mentum of one bee whence it is sucked up through the proboscis by 

 the other. All of these statements, however, concerning the feeding 

 of the brood and the differences in the diet need to be verified. They 



