STRIPED MUSCLE OF WASP ol 
transversely cut and stained sections of fibers they are with 
difficulty distinguishable from the very abundant sarcosomes. In 
general they are slightly larger than the large sarcosomes. The 
fiber is composed of relatively very robust sarcostyles, among 
which the sarcosomes are scattered in great profusion. In the 
photograph the sarcostyles appear white, the sarcosomes and 
nuclei black (fig. 12). The sarcostyles are circular in outline 
in transverse section and vary slightly in diameter. The sar- 
cosomes are irregularly stellate or fusiform bodies resembling 
somewhat tendon cells as seen in cross-section (figs. 45 and 48). 
Longitudinal sections (figs. 138 and 23) show that the sarcosomes 
are of irregular form, but frequently apparently oval, and that 
they are arranged in single and double columns between adjacent 
sarcostyles. Figure 21, a drawing of five adjacent sarcostyles in 
longitudinal section, shows a frequent arrangement of the sar- 
cosomes, namely, in oval group. 
Two other important facts are revealed in figure 21. First, 
the regular alignment of the telophragmata in adjacent sarcostyles 
indicates that they span also the intersarcostylic space. This 
is denied by Thulin,?* who claims that a telophragma is lacking 
in the wing muscles of Coleoptera, Diptera, and Hymenoptera. 
But his illustrations show clearly that his conclusions are based 
upon secondarily modified fibers, that is, fibers that have suffered 
distortion and rupture. That the intersarcostylic representative 
of the telophragma is very delicate is demonstrated by the 
ease with which it ruptures in fixed and mechanically handled 
tissue. But that it is actually present is further proved by such 
examples as illustrated in figure 22 where a slight bending and 
distortion has simply drawn out, and in consequence emphasized, 
the intersarcostylic portion of the continuous telophragma. 
Where the sarcosomes are very abundant, however, as in figures 
13 and 23, the telophragmata cannot be traced among the groups 
of sarcosomes. Here the telophragma must be either fenes- 
trated or have become ruptured and probably completely 
destroyed. In such areas also the primarily regular (normal) 
transverse alignment of similar portions of adjacent sarcostyles 
has become vitiated. 
THE AMERICAN JOURNAL OF ANATOMY, VOL. 27, NO. 1 
