REPORT OF THE STATE ENTOMOLOGIST I907 253 
-Libellulidae. h is situated between the first and second hamules. 
It is my opinion that the first pair of hamules are developments of 
the posterior and outer sides of the anterior lamina, while the sec- 
ond pair are the terminations of the posterior portion of the frame- 
work which swings around close to segment 3 in this figure. This 
point is discussed, more fully, later. o shows the penis and seminal 
vesicle developed on segment 3. 
| The next figure (d) is a sketch representing the relation of 
parts typical for the entire suborder Zygoptera. The most 
apparent difference between this and the two figures explained 
above is in the location of the penis, p this being on the 
2d segment here, and seemingly in an exactly homologous po- 
sition to that of the sheath of Anisoptera. The supporting 
framework is constructed on the same plan as that of Anisoptera, 
m being the anterior portion which passes under the penis 
and also under the lobes of the anterior lamina and mn the 
posterior portion intimately associated with the hamules h. Only 
one pair of hamules is noted; however, associated with this fact, 
one must notice the remarkable development of the posterior 
portion of the anterior lamina of which the lobed portions 
divided well back, appear like a second pair of hamules, and 
no doubt so function, while the smaller chitinized structure 
between the lobes of the lamina and just anterior to and over 
the penis, formed by an infolding of the under side of the 
anterior lamina, appears analogous in position to the sheath of 
RiCuEpPCHicminin tie Otnem. suborder. he) vesicle o 1s) clearly 
marked on segment 3. 
Ontogeny 
These peculiar structures develop in late nymphal life. They 
originate out of folds and thickenings of the epidermis, formed 
chiefly during the last nymphal stage beneath the chitinized 
cuticle. By a careful removal of the cuticle, the underlying 
parts may be exposed to view while still in a very rudimentary 
condition. 
Figure 19 (m) represents the 2d segment of a nymph of 
Eibellula pulchella in the last nymphal stage in the 
ventral view with the cuticle removed, and a cross-section of 
the same is shown at (m). In (m), / is the anterior lamina; k, 
