Nov., 1920] Zygopterous Dragon Flies 21 



I. Agrionidae. 



1. Megapodagrionince. 



2. Philogangince. 



3. AmphipterygincB. 



4. EpallagincB. 



5. PolythorincE. 



6. Agrioniiice. 



7. LibeUagince. 

 (8. Platystictina'O 



II. Hemiphlebidae. 



9. HemiphlebincB. 



I. Agrionid^. 



This family is roughly defined by a combination of charac- 

 ters: two rows or more of cells between Mia and M2 at the level 

 of the stigma; no oblique vein between M2 and Rg distad of 

 the subnodus; naiadal labium cleft. 



Known exceptions to the first character are Trineuragrion 

 and Tatocnemis and the genera in the Platystictinse. The 

 inclusion of the latter here of course depends on the correctness 

 of Fraser's identification"* of the Protosticta naiad. When the 

 study of the penes showed that Hypolestes (Ortholestes) was not 

 Lestid but belonged near Amphipteryx the Selysian definition 

 of Zygopterous families had to be discarded. That discovery 

 put Hypolestes with its two antenodals into the Agrionidae. 

 With the bar against two antenodals in the Agrionidee lifted, the 

 Megapodagrioninas became Agrionid on the strength of their 

 extra sectors and the cleft labium in the naiad, {Thaumatoneura^ , 

 Argiohstes^). 



1. Megapodagrioninae. Figs. 91-124. Nesolestes, {Protolestesy (Allo- 

 lestes), Neurolesles, Podolestes, Trineuragrion, (Melanagrion) 

 Ripkidolestes, Argiolestes (Metagrion) Wahnesia, Podopteryx, 

 Paraphlebia, Thaumatoneura, Rhinagrion, (Phenacolestes), Tatoc- 

 nemis, Megapodagrion, Heteropodagrion, Dimeragrion, Allo- 

 podagrion, (Lithagrion) Philogenia, Heteragrion, (Mesagrion), 

 Oxystigma^. 



The most primitive genera in the above list are Podolestes 

 and Rhinagrion. These in their simple venation, simple penes 



^ Rec. Ind. Mus. XVI, p. 465, 1919. 

 6 Calvert, Ent. News 26, p. 300. 



^ Tillyard, Biology of Dragonflies, p. 278, "Mask — resembling that of the 

 EpallagincB." 



' Parenthesis indicates that the penis has not been studied. 



» Probably Lestoidea belongs in this subfamily. Its penis is unknown. 



