HISTOLYSIS OF FAT-BODY OF APIS 593 



cells, more numerous in the thoracic region where they are 

 destined to be replaced by the thoracic muscles, undergo a 

 'precocious degeneration,' as stated by Perez. This change com- 

 prises in the bee larva the dissolution of the cell wall and the 

 release of the cell contents into the blood space. Those globules 

 which appear not fully developed still stain with the nuclear 

 dyes, and especially with Heidenhain's haematoxylin ; they are 

 still small in size and compact in structure, without the vacuo- 

 lated center which seems to be characteristic of a late stage of the 

 normal development. This precocious change is apparently not 

 associated in the bee with the presence of any unusual cellular 

 element such as the leucocyte, nor of any condition other than 

 the early development of large masses of tissue in this region. 



3. The metabolic significance of the changes in structure 



Tracing the fate of the larval food through the nutritive 

 mechanism, the following resume may serve to correlate the 

 nutritive process with the cellular metamorphosis. 



The partially digested food of the early larva, the 'royal 

 jelly' elaborated by the worker bees, contains carbohydrate, fat, 

 and protein. This special food the queen larva receives all during 

 larval growth; after the third day the worker is fed considerable 

 amounts of honey and undigested pollen, and the male still 

 larger proportions of pollen. The fat and practically all of the 

 carbohydrates taken up by the fat-body are stored as fat-droplets^ 

 until, at the beginning of metamorphosis, these droplets are 

 worked over into the so-called albuminoid globules developed 

 from granules arising from the nucleus. 



Since there is very little protein in honey, the bulk of the 

 nitrogeneous food comes from pollen, chiefly in the form of nucleo- 

 proteids. These are presumably stored up as nucleoproteids in 

 nuclear chromatin and the chromatoid granules, and as more 

 simple proteins in the acidophile cytoplasmic matrix. In the 



^ Nakahara reports glycogen in the developing fat-cells of Pieris demonstrated 

 by Gage's methods. Glycogen could not be demonstrated in vitro in these tissues 

 by the ordinary chemical test of caustic hvdrolvsis and Treatment with iodine. 



