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REPORT OF THE STATE ENTOMOLOGIST 1907 261 
In (k) is a sagittal section from the 2d segment of Cordulia with 
the following structures noted, the letters of which indicate the same 
structures as in the other figures. e is a portion of one side of 
the posterior portion of the framework 
heretofore described, which is always 
intimately associated with the posterior 
hamules. Where the hamules are well 
chitinized and developed, this part of the 
frame is correspondingly developed. 
The hamules appear in some cases to be 
spread along posteriorly on this frame- 
work, adding to its thickness. It can be 
followed easily in all the figures. f is 
one of the posterior pair of hamules. 
This hamule in all figures here shown is 
well developed and in some cases very 
decidedly hooked at its upper point. g 
is the anterior portion of the framework 
which passes beneath the anterior lamina 
where we find but one pair of hamules, 
and in this figure, and those following, 
it passes below and posterior to the first 
pair of hamules derived from the an- 
Hig28 terior lamina. This portion of the 
framework is the direct support of the penis in Zygoptera and of 
the sheath in Anisoptera. h is the first pair of hamules developing 
just before g from the posterior edge of the anterior lamina. ‘The 
lamina is shown at 7 covered with hairs on its posterior and ventral 
surfaces. The first hamule h is not well developed; however, it is 
so far formed that one can easily homologize it with those more 
fully developed in any of the following figures. 
In (/), a sagittal section of Didymops, is. shown a farther and 
decided development of the first hamule marked h in the figure 
above it. The other structures are similarly placed and easily seen 
to be homologous. 
In (m) a very marked development of the first hamule is 
seem, it Deine, mm tis Case, a@limosr as lame as wie secomel 
hamule. In (m), Tachopteryx, is to be noted the beginning of 
the lobed condition of the first hamule so well shown in (0), 
Ophiogomphus. In other respects, the parts are similar and 
similarly placed to those of the preceding figures. In (0) is pre- 
sented, perhaps the most extreme development in the way of 
