PHILIP A. MUNZ II 



This peculiar little group of four genera is a rather compact one, but 

 shows within itself the ever present tendencies of specialization to 

 be found in the other subfamilies. It retains a rich venation with 

 many cross-veins, but has these fewer in number in the higher 

 genera, has petiolation become more advanced, has some of the 

 sectors tend to become attached to the principal veins, and has M2 

 becoming branched from Mi beyond the subnodus. Polythore 

 (fig. 2) and Euthore (fig. 3) are the two more generalized, Cora 

 (fig. 5) and Chalcopteryx (fig. 4) the two more specialized genera. 

 The fact that the Polythorinae are discussed first does not mean 

 that they are the most generalized Zygoptera; their quadrangle 

 and the continuing of the direction of Mi_3 by M1+2 rather than by 

 M3, as well as their petiolation, gainsay this. However, they are 

 the most distinct group and must have separated from the others 

 at rather a low level. 



The Agrioninae 



Venationally this group is quite distinct from the Epallaginae; 

 however, Schmidt (1915) working on the male genitalia, finds 

 there no basis for such a division. The Agrioninae consists of the 

 Vestalinae as defined by Dr. Needham (1903a) and can be dis- 

 tinguished from the Epallaginae and Disparocyphinae by the 

 following venational tendencies: Mia has a course parallel to that 

 of M2, the stigma becomes diffuse and finally atrophies altogether; 

 and the vein Cu2 in most forms has a branch Cuoa running toward 

 the hind margin of the wing. Vestalis (fig. 18) , Heterina (fig. 19) and 

 Lais (fig. 20) do not possess this branch, but the facts that the 

 stigma may be lost, that M^ is parallel to M2, that the quadrangle 

 becomes convex above, that some of the sectors tend to become 

 attached to the longitudinal veins, and that there is no petiolation- 

 and but slight reduction in the number of antenodals, indicate 

 affinities with the Agrioninae rather than the Epallaginae. The 

 subfamily Agrioninae has its own methods of specialization, but its 

 line ends in itself and shows no relationship to higher forms. 



Aside from the Vestalis-IIeterina-Lais group, which is the most 

 distinct, the remaining genera can be divided into those which 

 have Cu2a running perpendicular to the hind margin of the wing or 

 toward the base of the wing, and those in which it is bent away 



MEM. AM. ENT. SOC, 3. 



