PHILIP A. MUNZ 



7 



Fig. B. Venation of Argiocnemis. 



As an example of a wing of the Coenagrionidae, Argiocnemis may 

 be used, for which see fig. B. The notations are largely as in fig. A, 

 except that there is no basal radial space present and that the ante- 

 nodel spaces are few enough to be numbered ; the first antenodal 

 space is that between the base of the wing and the first antenodals, 

 the second antenodal space is that between the first and second 

 antenodals, and the third antenodal space is that between the second 

 antenodals and the nodus. Cu2a is not present. 



Explanation of Figures 

 In referring to figures. A, B, C, etc. are the text figures, while 

 figures I, 2, 3, etc. are to be found in the plates at the end of the 

 paper. 



II— A DISCUSSION OF THE PHYLOGENY 



Passing now from a review of the system of nomenclature used, 

 the next step is the consideration of the phylogeny of the Zygoptera 

 and their relationship to other groups. 



The Anisozygoptera 



In his treatise on fossil insects, Handlirsch (i 906-1 908) created 

 as a new suborder the Anisozygoptera, for many fossil forms and 

 for the living genus Palaeophlebia, to which he gave the name 

 Neopalaeophlebia, since the former name was preoccupied. Dr. 

 Calvert (1903), however, had already used the name Epiophlebia 

 •for Palaeophlebia and it is his name that must be used. This 

 genus according to Handlirsch falls as readily into the Anisoptera 

 as the Zygoptera and to keep the two groups distinct, a third 

 intermediate one is necessary. Epiophlebia (fig. i) is the only 

 known survivor of a large suborder of Mesozoic insects and is 



MEM. AM. ENT. SOC, 3. 



