REPORT OF THE STATE ENTOMOLOGIST 1907 251 
formed by the infolding of the thin connective there, that the 
primitive receptacle for the sperm mass, whatever may have been 
its nature, found its origin. The posterior part of the sternum of 
the 3d segment is liftle affected, and the anterior part of that of 
the 2d segment forms the well known, usually flat, “ anterior 
lamina.” If the sternum of each abdominal segment consisted 
originally of two parts, sternum and sternellum, anteriorly and pos- 
teriorly situated, the penis and hamules and their supporting struc- 
ture may be supposed to have developed upon the sternellum of the 
2d segment, while the anterior lamina represents the anterior 
division, the sternum of that segment. 
Figure 18 is a diagrammatic representation of the relations 
of the appendages to the sterna of the first three abdominal 
Se Silemtsu (lem 2manders))a(@) aisma eenerall Sketch jof Seoment 
2.with parts of 1 and 3. Segment 2 is divided into s# sternum 
Fig. 18 
and stl sternellum. This:‘sketch is merely to aid in the location 
of the complicated parts of the following figures. The second 
figure (b) shows the relation of the genital structures in the Libel- 
lulidae. On segment 1 no very prominent structures are noted. 
Small pits are to be seen just anterior to segment 2. Such pits are 
found among the Anisoptera and in the Zygoptera, not only on seg- 
ment 2 but also on segment 3. On segment 2 we have at ¢ the 
anterior lamina, at m the anterior portion of the framework which 
supports the sheath of the penis in Anisoptera and the penis 
itself in Zygoptera. This part of the framework is firmly at- 
tached to and apparently developed from the under side of the 
anterior lamina. s is the sheath of the penis resting on the 
framework below. PMissone or tie esinele pair or hamules 
here developed, attached anteriorly to the framework m, posteriorly 
to the ends of the U-bar s. Between and joining these ends of s 
there is only a line of chitin m here. This latter is much better de- 
