574 GEORGE H. BISHOP 



on the one hand, storage of food materials especially adapted to 

 tissue growth and, on the other, a mechanism by which, during 

 pupation, this reserve is further modified into food constituents 

 suitable for immediate utilization by imaginal tissues. With a 

 study of these two phases of the activity of the cells the following 

 discussion concerns itself. 



DEVELOPMENT AND TRANSFORMATIONS IN STRUCTURE OF THE 

 FAT BODY CELL OF THE BEE LARVA 



).. Historical 



Except for quite recent papers, the literature on the insect fat- 

 body has been reviewed so thoroughly that repetition is super- 

 fluous (Anglas, '00; Perez, '02, '11). In general, three lines of 

 attack have been made on the question; 1st, the investigation of 

 the larval fat-body as the precursor of the imaginal fat-body; 

 2nd, the study of the mechanism by which the larval fat-tissue 

 is histolyzed (autolysis of phagocytosis), and, 3rd, consideration 

 of the fat-body as a larval food storage reservoir. The ele- 

 ments concerned are the fat-tissue cells with their fat-globules 

 and albuminoid granules, the oenocytes, the phagocytes, and 

 leucocytes. 



a. Metamorphosis to imaginal fat-body. Four methods of 

 origin have been assigned to the imaginal fat-body: 1) from em- 

 bryonic cells developed from fragments of the fat-cells (Auerbach, 

 '74) ; 2) from embryonic cells developed from degenerating muscle 

 cells (Anglas, '00); 3) by reformation of dispersed fat-cell frag- 

 ments about the old cell nucleus (Koschevnikow, '00) ; 4) by 

 persistence of certain larval fat-cells to form the imaginal tissue 

 (Ganin, 75; de Bruyne, '98; Berleze, '01; Perez, '02, '11). The 

 last interpretation seems best established. 



h. Destruction of larval fat-body; autolysis and phagocytosis. 

 The discussion of the release of the food materials of the larval 

 fat-body cells has taken to some extent the form of a debate as 

 to the respective merits and relative prevalance of autolysis, i.e., 

 histolysis without attack by phagocytes, and phagocytosis or 

 destruction by leucocytes or other wandering cells. Five inter- 

 pretations have been placed upon the facts : 1) The development 



