FORE-GUT OF CORYDALIS CORNUTUS L. 609 



face of the imagiiial discs. This type of histogenesis is described 

 for the fore-gut muscles of Musca vomitoria (Kowalevsky and 

 Perez), Gastrophilus (Vaney), Malacosoma castrensis (Deegener 

 '08), Isosoma graminicola (Van Leeuwen '07), and some others. 



2. The regeneration of the imaginal muscles from the larval* 

 muscle nuclei and cytoplasm. The fibrillar part is destroyed 

 while the nuclei persist, divide and form myoblasts. These form 

 new fibrillae. This view, or a modification of it, is held by Korot- 

 neff ('92), Anglas ('00) for some muscles, Breed ('03), Deegener 

 ('04) and Berlese. 



3. The regeneration of the imaginal muscles from small ima- 

 ginal nuclei present in the muscles. These nuclei become active 

 at the time of pupation, while most or all of the larval nuclei 

 degenerate. This type of regeneration is a complicated one and 

 the investigators who advance this theory always admit that at a 

 certain period it is impossible to tell whether one is dealing with 

 rejuvenated larval nuclei or the so-called imaginal nuclei. This 

 view has been put forward by Karawaiew ('98) for Lasius niger 

 and Russ ('08) for Anaboha laevis (Trichoptera) . 



In discussing the histolysis of the fore-gut muscles of Corydalis 

 I stated that this process ended about four days after the time of 

 pupation. As the changes in the epithelium are not governed by 

 the time element so much as by the individual pupal conditions 

 so also is the muscle histolysis and histogenesis. 



By examining figure 22 one notes that the larval nuclei clearly 

 show a rejuvenated condition. They are arranging themselves 

 in rows, while in the cross sections of the longitudinal muscles 

 one can see faint indications of forming fibrillae. Leucocytes are 

 quite numerous and are filled with densely staining granules. In 

 a slightly more advanced condition (fig. 23) the longitudinal 

 muscles clearly show the cut ends of forming fibrillae. The 

 circular muscles do not show well in the figure. It is probable 

 that figure 23 shows about the same stage of muscle regeneration 

 as figure 22 although figure 23 is from a pupa nearly eight days 

 old. However, further cephalad in the latter the fibrillae show 

 clearly in the circular muscles. During this time one finds nuclei 



