MUSCULATURE OF CULEX PUNGENS. 29 I 



('92), Bataillon ('90), Needham ('oo) and Breed ('03) all find that 

 phagocytes play no part in the degeneration proper of muscles. 

 Phagocytosis may, or may not occur, but whenever it does it is 

 always a secondary process. No one of these authors attempts 

 to explain the primary cause of the degeneration, though it is 

 variously described as a morphological, physiological and chem- 

 ical change. Such a change may be accounted for in the sub- 

 catobolic conditions involved in a deficient nutritive supply. At 

 the end of physiological activity of the larval organs of an holo- 

 metabolic insect the nutritive supply is diverted from these organs 

 to the parts which are to evolve the new organs of the imago. 

 Such a process would result in the phenomena above described, 

 a condition which is amply illustrated in certain pathological 

 changes in the tissues of higher organisms when the nutrition is 

 interfered with. 



The further phenomena attending the dissolution of the muscles 

 is not constant. As above stated, there appears, in the majority 

 of cases, a dissolution of the muscle substance accompanied by 

 a hypertrophy of the nuclei. In such cases the striation is early 

 lost, the nuclei take an oval or spherical appearance and stain less 

 regularly. In fact the most marked evidence of early degeneration 

 among the larval muscles of Cnlc.v is the hypertrophy of the 

 nuclei and changes in their morphology and staining properties. 

 Instead of showing a chromatin network and an evenly stained 

 nuclear substance, there are larger or smaller deep-staining 

 granules which soon become arranged about the periphery and 

 contained within a nuclear membrane. The nucleolus disap- 

 pears and the whole nucleus breaks up by rupture of the mem- 

 brane and the granules become scattered. Plate X., Figs. 2, 3 

 and 4, show the evolution of this process. The complete 

 destruction by rupture and dissociation of the granules has been 

 repeatedly seen. Such are the small dark staining bodies found 

 scattered among the other detritus in the body cavity late in the 

 process of degeneration. Their fate is then similar to that of other 

 fragments of muscle tissue to be described later. 



In the present study no other condition of the nuclei was ob- 

 served than that of total disintegration by rupture of the mem- 

 brane after the entire nuclear substance had become condensed 

 into a few irregular granules at the periphery. 



