MUSCULATURE OF CULEX PUNGENS. 289 



Here the sheath about the bundle, not being stretched away or 

 broken by the increase of material within, remains longer than 

 the contractile substance showing the original limits of the muscle. 

 The nuclei in such cases pass through the same chromatolysis 

 as in the above instances. 



The late stages of muscular degeneration are seen in the body 

 cavity. Fragments, either carried there by phagocytes, or swept 

 there by some other agent, undergo a fatty degeneration which 

 will be described later. Having thus briefly considered the 

 phenomena found in Ciilcx, a discussion of the various points 

 and a comparison with the results obtained by others may be 

 made. 



It is the primary factor in this muscular degeneration which 

 appears difficult of determination and upon which authors have 

 expressed materially different opinions based upon observations 

 upon the same or different animals. Kowalevsky ('85) notes 

 the active interference of phagoctes within five to six hours after 

 the change to the nymphal stage (Musca vomitoria), commencing 

 in the first segments of the body where there is no indication of 

 degeneracy in the muscles ; nucleus, sarcoplasm, and striations 

 are absolutely normal from a morphological standpoint. The 

 progress is rapid so that by the seventh or eighth hour all the 

 muscles of the first segment are destroyed. 



Bruyne ('98) in the study of the same animal, agrees with 

 Kowalevsky as to the time of the appearance of leucocytes. In 

 nymphs of one and two days, entire muscles were reduced to a 

 conglomerate mass of angular fragments of variable dimensions 

 but having preserved their striations. Almost all are enclosed 

 in leucocytes, while many of the latter, still empty, are found 

 between the fragments of muscular debris. He defines these 

 leucocytes as little protoblasts moving in an amaeboid manner, 

 pushing out their pseudopodial extremities through the sarco- 

 lemma and into the muscular substance. However, Bruyne 

 does not consider this the beginning of the degeneration, but 

 describes areas showing at once a transition from the muscle fas- 

 ciculi, still striated, with nuclei in different stages of hypertrophy, 

 to fragmentation of the contractile substance and change in the 

 staining properties of the sarcoplasm, all of which occur without 



