448 



Tabular Summary 



Paleodictyoptera 



Protodonata 



Odonata 



Dictyoneuridae 



Meganeuridae 



Protagrionidae 



Paralogidae 



Anisozygoptera 

 Archizygoptera 



Zygoptera 

 Anisoptera 



Wings moderately 

 broad at base 



Large number of ir- 

 regular cells 



Wings moderately 

 broad at base 



Wings broad or nar- 

 row at base 



Large number of Reduction 

 polygonal cells 



Subcosta ending in Snbcosta ending 



in the 



number of polyg- 

 onal cells 



costa beyond the 

 middle of the 

 wing; not forked; 

 no nodus 



Radial sector not 

 crossing media 



Radius and media 

 not fused at base 

 and no arculus 

 formed 



Stigma absent 



about the middle 

 of the wing; not 

 forked ; no nodus 



Subcosta ending at 

 middle of the 

 wing; forked; no- 

 dus present 



Cross-veins between A n t e n o dal cross- 



costa and subcosta 

 22-50 or more 



veins much re- 

 duced, u s u al 1 y 

 more than two in 

 number 



Radial sector appar- Radial sector cross 



ently not 

 media 



crossing 



Radius and media 

 fused but no arcu- 

 lus formed 



Stigma absent 



M, arising proximad 

 of end of subcosta 



ing media 



Radius and media 

 fused and arculus 

 frequently formed 



Arculus near the 

 base of the wing 



Stigma sometimes 

 present 



Stigma not support- 

 ed by oblique 

 cross-veins or sup- 

 plementary sectors 



M 2 arising near the 

 subnodus, often 

 slightly proximad 



Stigma cells numer- 

 ous 



Wings broad or nar- 

 row at base. 



Still greater reduc- 

 tion in number of 

 polygonal cells in 

 Zygoptera. 



Subcosta often end- 

 ing proximad of 

 the middle ; 

 forked ; nodus 

 present. 



Antenodal cross- 

 veins often re- 

 duced to two in 

 Zygoptera ; more 

 than two present 

 in Anisoptera. 



Radial sector cross- 

 ing media. 



Radius and media 

 fused and arculus 

 always formed. 



Arculus further dis- 

 tad from the base. 



Stigma only occa- 

 sionally absent. 



Stigma supported by 

 oblique cross- 

 veins, supplemen- 

 tary sectors, or 

 both. 



M, arising 

 subnodus 

 siderablv 



at the 

 or con- 

 bevond. 



Stigma cells few in 

 Zygoptera. 



