FORMATION OF THF PRONYMPH FROM THF LARVA. 299 



muscle ; they are surrounded and enclosed by immigrant 

 blood corpuscles. Frequently, however, the nuclei remain 

 after the complete histolysis of the fibre, and are isolated by 

 the falling apart of the granule cells. In this case they lie 

 free in the blood, but are ultimately seized upon and disinte- 

 grated by amoeboid corpuscles. These nuclei, when enclosed 

 within the leucocytes, lose their vesicular form and become 

 converted into splieroid or ovoid masses of material, which 

 stain deeply with carmine. The blood corpuscles attack the 

 muscles with such energy that on the second day (third day) 

 scarcely any remain which are not converted into granule cells. 

 These, although loaded with angular and spheroidal pieces 

 of muscle, do not cease to move by minute pseudopodia. 

 Moreover, they continue to feed and attack the cells of the fat 

 bodies.' 



There are two points in the foregoing description to which I 

 would add a few words from m}- own observations. 



Kowalevski appears to think that all the leucocytes (phago- 

 cytes) enter the muscle and fat bodies from the blood ; at least, 

 he says nothing of their rapid multiplication within these 

 tissues. Many of the leucocytes within the muscles and fat 

 bodies contain from four to six or eight nuclei, and are evi- 

 dently undergoing rapid proliferation. 



The second point is in relation to the muscle nuclei. It is 

 true these are frequently seen surrounded by a clear proto- 

 plasmic area in the substance of the muscle, or free in the 

 blood ; but I cannot convince myself that the areole is a 

 phagocyte. It appears to me that the leucocytes attach them- 

 selves to the exterior of the nucleus and perforate its capsule 

 by sending a pseudopodium into its interior, after which the 

 nuclear fluid disappears, and the chromatin falls into a mass 

 which exhibits no definite structure. The remains of the nucleus 

 then pass into one of the adjacent leucocytes and disappear. 



b. The Histolysis of the Hypodermis, and the Formation of the 



Paraderm. 



Reaumur was acquainted with the fact that the transforma- 



