14 ROBERT H. BOWEN 
In addition to these observations on the acrosome, I have been 
able also to add some facts corroborative of the nebenkern history 
which I have described in the Hemiptera (Bowen, ’22 b). Thus 
I have found that the nebenkern passes through a process of 
differentiation, which, in the beginning at least, is strikingly like 
that in Brochymena, and I have been unable to make out the 
thread-like formation figured by Giglio-Tos and Granata (’08). 
As in the Hemiptera, the chromophilic substance gradually con- 
denses and eventually disappears entirely, figure 21 being a 
cross-section of the nebenkern just before its final disappearance. 
Following this, the nebenkern divides. The condensation of 
the chromophilic substance in the grasshopper nebenkern takes 
place so rapidly that the nebenkern divides some time before it 
begins to elongate, the two halves rounding up in a very charac- 
teristic manner (fig. 23). Another case is thus added to those 
already described, which show that the complete division of the 
nebenkern follows immediately upon the disappearance of the 
chromophilic substance. With respect to the condition of the 
chromophilic substance at the time the nebenkern begins to 
elongate, an interesting series is thus formed by the grasshopper, 
the bug, and the beetle (and possibly the butterfly). 
Finally, in Cajal preparations, I was able to demonstrate in 
the nebenkern (as in the Hemiptera) the occurrence of a material 
which I have called the ‘central substance.’ This stuff in the 
grasshopper nebenkern is by no means as regular in its arrange- 
ment as in Kuschistus, for example. Instead, it forms a very 
indefinite mixture of granular (and thread-like?) elements which 
combine to make an exceedingly complicated picture (fig. 22). 
When the nebenkern halves elongate this central substance is 
drawn out also, and seems eventually to form a delicate thread- 
like core for the mitochrondrial tail sheaths. The vesicles which 
I have described on the tail sheaths in Hemiptera appear like- 
wise in the grasshoppers, but are by no means so conspicuous. 
Their general history seems not unlike that in the Hemiptera. 
