2.62 NEW YORK STATE MUSEUM 



hamules. Both the first and the second are remarkably lobed, 

 hairy and chitinized. The first has reached the extreme in 

 regard to its bilobed condition. The second hamule has a 

 sharp, strong prong pointing anteriorly or in the opposite di- 

 rection to the lobes of the first pair.. The anterior lamina is 

 plainly seen anterior to the hamules with the framework in 

 the same position as in other forms. 



We may, I think, assume here that these figures represent 

 a developmental series in respect to the production of the first 

 pair of hamules. 



Recapitulation of the important points in the foregoing 

 paper: 



1 In Anisoptera the penis is found upon the 3d abdominal seg- 

 ment, while in Zygoptera it is found on the 2d. It seems probable 

 that the penis in Zygoptera is developed from the 2d segment, while 

 that in Anisoptera is developed from the 3d and extended upon 

 the 2d. However, evidence from embryology is needed here. 



2 The supporting framework in both suborders is built on 

 the same plan. 



3 The situation of the posterior or second pair of hamules 

 is homologous in the suborders, as well as the situation of the 

 seminal vesicle. 



4 In Zygoptera only One pair, the posterior, of hamules is 

 found' unless we assume that the peculiarly developed posterior 

 lobes of the anterior lamina here, are to be taken as hamules. 



■5 No sheath of the penis is found in Zygoptera homologous 

 in"positioh to that of Anisoptera, but we may assume that the 

 chititii-zed structure between the posterior lobes of the anterior 

 limina serves the same function as the sheath in Anisoptera, 

 because of its location before and over the penis. 



6 The sheath in Anisoptera and the penis in Zygoptera are 

 in homologous positions, that is, directly upon the anterior por- 

 tion of the framework which passes across below them. 



7 Evidence seems to show that the anterior lamina, first 

 pair of hamules and the anterior portion of the framework, 

 that is, the part extending under, and attached to the lower 

 surface of the anterior lamina, are developments of the sternum,' 

 while all other structures on segment 2d come from the sternellum. 



8 The Libellulinae among the Anisoptera seem to show the 

 least specialized male genital apparatus, while it is difficult to. settle 

 which is so among the Zygoptera. The extreme in specialization of 

 these parts is perhaps found among the Gomphidae. 



