774 Wisconsin Academy of Sciences, Arts, and Letters. 
the figure as a portion of the wall of the salivary gland near 
the mouth. 
The two reservoirs of the salivary glands of Libellula f- 
maculata are found on the basal part of the hypopharynax (fig. 
32). Each receives a duct from one of the salivary glands, 
each duct where it enters the reservoir is much thicker than 
at other parts; this thickness is due to the wall of the reservoir 
extending for a short distance out over the duct and forming 
a second wall much thicker than the real one (fig. 33). From 
the more rounded basal part of each reservoir a short duct 
leads off, these two ducts soon unite to form a common one 
(fig. 35) which opens at the base of the hypopharynx. 
The wall of the reservoir is peculiar in structure and, at 
first view, one is apt to consider it as composed of two layers 
of cells ; one, the inner, protruding beyond the other. A surface 
view of the inner surface (fig. 36) shows a number of separ¬ 
ated cells having no connection with each other until the focus 
is dropped and then the outer portion of the wall comes into 
view. In many of the specimens examined these cells, from 
this inner surface view, showed an irregular or scalloped mar¬ 
gin; whether this is due to shrinkage I am unable to say as 
all the specimens studied were from preserved material. A sec¬ 
tion of the wall (fig. 37) shows that the outer half or third 
is entirely continuous and regular and that the inner part is 
composed of wide prolongations which give to the wall a pa¬ 
pillate appearance. These protruded parts make up the larger 
part of the wall. Ho cell boundaries can be seen at any part 
but one would expect to find them dividing the protruded parts 
from each other or where the wall is thinnest; this is the 
way they have been figured by Berlese (1, Fig. 584, B, II). 
Over the inner surface of the leservoir the cuticula is quite 
thick but lacks the taenidial structure that is present in the 
ducts. 
A study of the reservoirs, both in surface view and in sec¬ 
tions, fails to convince me as to the true nature of the nuclei of 
the cells. In both these views very many cells are found that 
have all the appearance of being binucleate. In nearly every 
