350 



globules break loose from the cell, and are apparently 

 dissolved in the blood. 



The disappearance of the larval cells is not, however, 

 entirely one of chemical disintegration; definite phagocytosis 

 of the cells also occvjts, but its action is quite secondary to 

 that of the chemical disintegration. Indeed, it is improbable 

 that there are at this stage enough leucocytes in the blood of 

 Nasonia to bring about the destruction of the larval integu- 

 ment' — not to mention the destruction of other larval organs. 

 : That the process does occur, however, is quite certain ; 

 leucocytes may frequently be seen lying upon or within the 

 disintegrated cells, and filled, at times, with degeneration 

 globules, which they have recently ingested (fig. 31). They 

 are the Kornchenkugeln of Weismann. 



Sometimes the cell contents do not break up into these 

 minute "pseudo-nucleated" globules, but the whole mass 

 undergoes granular degeneration and produces a large ball 

 (fig. 30), which, after lying for some time within the cell 

 membrane, breaks loose, and tumbles into the general body 

 cavity; a few globules generally remain within the cell mem- 

 branes, which now appear as irregular, empty hulks, below 

 the developing imaginal integument. Sometimes, again, the 

 cell contents may degenerate into large hyaline spheres, about 

 the size of leucocytes, each containing several heavily-staining 

 granules (fig. 28). 



In the body cavity the big granular spheres are fallen 

 upon by the leucocytes, and by the intervention of these, and 

 to a certain extent, apparently, by a process of solution, they 

 gradually disappear. This type of cell disintegration is especi- 

 ally clearly seen in the larva about sixteen hours after 

 defaecation. 



The process of integument destruction lasts nearly a 

 whole day; the cell contents first disappear, leaving only a 

 thin cell membrane, which, in turn, eventually disintegrates. 



Accompanying these changes in the integument there is 

 a total renovation of the underlying somatopleure. The larval 

 somatopleural cells are greatly overgrown, and present a large 

 nucleolus. Smaller embryonic cells, which have evidently 

 lain dormant within the somatopleure, begin to proliferate 

 during the period just preceding defaecation, and growing at 

 the expense of the larval cells which they absorb, finally 

 redevelop into a new somatopleure. The splanchnopleure, 

 covering the internal organs, undergoes similar changes. 



Meanwhile the imaginal discs have become active, and, while 

 the cells undergo further multiplication, begin to encroach 

 upon the places occupied by the disintegrated larval cells, 

 eventually replacing these entirely. The discs grow out in all 



