HISTOLYSIS OF FAT-BODY OF APIS 577 



Nakahara (17), in a research directed primarily to the func- 

 tioning of amitosis in the insect fat-body, reported incidentally 

 on the larval development of the fat-cell in Pieris. In 'second- 

 stage' larvae, apparently still very young, nuclear ramification 

 was observed, and in the ' third' stage spherical albuminoid glob- 

 ules in the cytoplasm; amitotic division of the nucleus occurred 

 with the production of as many as five nuclei to a cell. At a 

 late larval stage some of the albuminoid globules "begin to show 

 dark dots, taking basic stains, indicating that the transformation 

 of albuminoid substance into urates is beginning to take place" 

 (on the assumption that the basophile stain indicates the de- 

 generation of albuminous material to purine bodies, rather than 

 the acquisition of nuclear substance). "This possibly may be 

 regarded as one of the first signs of a histolytic process. Soon 

 afterwards, just before the larva enters the prepupal stage, the 

 nucleus loses its membrane and its structure becomes more or less 

 indistinct. This is, I believe, the sign of a karyolytic process, 

 which concludes the activity of the larval adipose cells." The 

 further progress of these structures is not followed. Amitosis in 

 the fat-cells is inferred to result in the increase of surface ad- 

 vantageous to active nuclear functioning. 



From these accounts may be derived a general description of 

 the fat-cell changes during growth and metamorphosis. The 

 conflicting details of various authors, while perhaps due in part 

 to faulty or incomplete observations of fact, are probably more 

 largely due to the actual differences in the details of the process 

 in the different orders of insects worked upon. It will be difficult 

 to compare these details critically until a more accurate knowledge 

 can be obtained of their physiological significance. 



2. Anatomical data. Structural changes accompanying cell 

 metabolism in the fat-body of Apis mellifica 



a. Material. Material was procured at closely timed stages 

 and examined consecutively with various stains. It was found 

 convenient to divide the larval and pupal development more or 

 less arbitrarily into periods according to the cell changes, as 

 follows : 



