344 bulletin: museum of comparative zoology. 



muscle nuclei are never digested by the leucocytes, but divide and form 

 cells — the " sarcocytes " — which give rise to " myocytes." The 

 " myocytes " then fuse with each other, either developing into imaginal 

 muscles or undergoing fatty degeneration to form the imaginal fat-body. 



Vaney (:00), who studied Gastrophilus, describes the larval muscles 

 as undergoing, during pupal life, a phagocytosis accompanied by the 

 formation of " Kurnchenkugeln." 



h. Orthorrapha. Hurst ('90) states that all of the imaginal muscles 

 are present in the young pupa of Culex. 



Miall and Hammond ('92, :00) find in Chironomus cells which re- 

 semble "Kornchenkugeln," but these do not result from the phagocyto- 

 sis of the larval muscles. The larval muscles of the head and thorax 

 seem to waste away gradually and uniformly while undergoing for a long 

 time no external chaugo of form. Some of the larval muscles remain in 

 the adult. 



Kellogg (:01) finds in Holorusia, with a generalized larval form, that 

 there is no phagocytosis. The larval muscles of the thorax undergo a 

 " selbstandige Degeneration " (Karawaiew, '98), while many new muscles 

 are added in the head and thorax during pupal life. In Blepharocera, 

 with a highly specialized larval form, he finds active pliagocytosis, but 

 apparently without the formation of " Kornchenkugeln." 



Lepidoptera. In a paper on the changes of the muscles in Tinea, 

 Korotneff ('92) states that all of the imaginal muscles are to be regarded 

 as metamorphosed larval muscles. The resorption of the muscles takes 

 place as follows : the nuclei and sarcoplasm of each fibre accumulate on 

 one side, and finally become separated from the fibrillar substance by a 

 longitudinal splitting. The imaginal muscles originate from this de- 

 tached strand, which is composed of the undifferentiated sarcoplasm con- 

 taining the nuclei, whereas the strand which is composed of contractile 

 fibrillar substance undergoes a chemical degeneration in which the 

 leucocytes take no part. 



De Bruyne ('97), in his study of Bombyx, finds that the initial cause 

 of the muscular destruction lies in the muscles themselves. There is 

 both autophagocytosis and leucocytic phagocytosis of the muscles, the 

 latter taking place only at a late stage in the destruction of the muscles. 



Berlese (;00, :01, :02*) obtains in Lepidoptera results similar to those 

 which he found in beetles. 



Perez (:00) states that he finds typical phagocytosis, and denies the 

 truth of Korotneff's observations. The results of these papers on Lepi- 

 doptera are apparently irreconcilable. 



