Apr. 5, 1924 
Anatomy of the Apple Maggot 
29 
may be formed from aggregations of sarcolytes, though he claims that such 
bodies contain at least one nucleated fragment. Janet (16), however, says that 
in the Muscidae some of the spherules are mere masses of sarcolytes which may 
or may not contain a muscle nucleus. 
In the pupa of Rhagoletis there are great numbers of spherules of muscle 
fragments (fig. 8, C) of the sort described by Janet, and the writer did not cer¬ 
tainly find any containing nuclei. Moreover, many of these spherules are formed 
deep in the body of the disintegrating muscle (A) where no leucocyte could get 
at them. They originate as mere groups of sarcolytes that adhere in small 
masses as the sarcoplasm dissolves about them, and that have been thus set 
free with a thin plasmic matrix cementing their elements together in globular 
form. Furthermore, leucocytes are always scarce; never are they found in such 
numbers as to account for the great mass of spherules that is eventually given off 
into the blood. 
The sarcolytes have been described by nearly all writers as retaining the 
original striation of the muscle fibers. In Rhagoletis the muscles lose their 
striation at the beginning of histolysis, and the sarcolytes are at first granular, 
though they soon acquire a striated appearance (fig. 8, C, D). Their “striation," 
however, is clearly secondary and appears to be due to a puckering of the surface, 
since the lines are always lengthwise and converge at the poles of the oval frag¬ 
ments. The material studied was taken from muscles or from drops of the body 
liquid of freshly killed larvae. The specimens were not fixed or hardened, and 
some were examined without staining, in order to be sure that nothing could be 
attributed to the effects of reagents. 
The bodies derived from the disintegrating muscles soon become very abund¬ 
ant in the blood. The spherules of sarcolytes are the most numerous and the 
most conspicuous, and most of them remain intact for a long time. After the 
pupa has acquired its final external form, however, they begin to disintegrate in 
a manner similar to that by which the fat cells go to pieces. They first lose their 
even contours (fig. 8, F), and later appear in very irregular forms or as mere 
loose aggregations of sarcolytes (G). This condition results evidently from a 
dissolving of the plasmic matrix that so far has held the component fragments 
together. By the fourteenth day after the formation of the puparium most 
of the sarcolyte spherules are in these various stages of disintegration. 
At about this time the blood of the pupa has a thick, granular, creamy con¬ 
sistency, so charged is it with the debris of both the muscles and the fat cells. 
Among this material there may be distinguished fat cells still intact, fat cells 
in various stages of disintegration, free oil droplets, masses of proteid granules 
from the fat cells, sarcolyte spherules still intact, spherules in all stages of dis¬ 
solution, free sarcolytes, caryolytes, and free muscle nuclei. In addition, there 
are leucocytes, various unidentified cellular elements, and great numbers of small 
grains of indeterminable origin. 
At the end of 18 days the sarcolyte spherules have been mostly broken up, 
and only free sarcolytes or dissolving groups of them (H) remain. The fat cells 
have likewise in large part disappeared. If the pupa is to become a fly in the 
fall of the same year, the contents of the blood are now rapidly dissolved; but 
with those that will not transform till the following summer, the processes of 
absorption are slower, and by the first of December the blood is still thick with 
the residue of larval tissues. 
Frequently there are to be seen in the blood small cells of the size of muscle 
nuclei, which contain several smaller bodies (E). These are evidently what 
Berlese (6) calls sarcocytes , or larval muscle nuclei that have divided by direct 
division into a group of small nuclei. These secondary nuclei, he says, become 
