98 



PHYSIOLOGY OF THE INVERTEBRATA. 



view of its chemical composition, and care, also, was taken to 

 investigate, individually, the juice as occurring in the cells 

 of three varieties of bees — queens, drones, and workers. 



Some preliminary microscopical examinations of this sub- 

 stance yielded the following results, which are quite in accord 

 with the subsequent chemical analyses : — 



(i) The food of the queen-bee larvas is the same during the 

 whole of the larval period ; it is free from pollen grains, which 

 have been reduced to a thickish but homogeneous juice by the 

 digestive action of the bee's stomach. 



(2) The food of the larval drones is also, during the first 

 four days of the larval period, free from pollen, and appears 

 to have been completely digested previously. After four days 

 their food is rich in pollen grains, which have, however, under- 

 gone a certain amount of digestion. The food-stuff of the 

 larvEO is probably formed from bee-bread. 



The following table gives the average percentages obtained 

 from several analyses : — 



All these food-stuffs are rich in nitrogen ; all were of a 

 greyish white colour ; and that of the queen-bee was the 

 stickiest, while that of the working-bees was the most fluid. 

 The greater part of the nitrogenous matter of the food was 

 proteid. The sugar present was always invert-sugar, whereas 

 the sugar in pollen grains is invariably sucrose. 



