THE SUBFAMILY LIBELLULIN^. 



259 



20. Abdomen with segments 2-4 carinated. (21.) 

 Abdomen with segments 2 and 3 carinated. (23.) 



21. Last antenodal nervure on the fore wings continuous. (22.) 



Last autenodal nervure on the fore wings not continuous. . 85. Fylgia. 



22. Fore wings with one row of post-triangular cells 86. Nannothmns. 



Fore wings with two rows of post-triangular cells *88. Fylla, 



23. All the wings, or at least the hind wings, with more than 



one cross nervure in the lower basal ceU. (24.) 

 Hind wings with only one cross nervure in the lower 

 basal cell. (2.5.) 



24. Fore wings with more than one cross nervure in the lower 



basal cell, or with only one near the base 79. Tetrathemis. 



Fore wings with only one cross nervure in the lower basal 



cell near the tip 78. Neophlehia. 



25. Trapezium of fore wings very narrow 84. Nannodiplax. 



Trapezium of fore wings broad or moderate. . (26.) 



26. Triangle of hind wings very small, its base placed half- 



way between its apex and the arculus 80. Brachygonia. 



Triangle of hind wings with its base nearly coinciding 

 with the arculus. (27.) 



27. Abdomen long, the terminal segments broad and depressed 81. Nephei-ieltia. 

 Abdomen short, the terminal segments not broad and 



depressed. (28.) 



28. Hind wings with one row of posl^triangular cells increasing. 87. Nannophya. 

 Hinds wings with two rows of post-triangular cells 



increasing *88^ Fylla. 



29. More than one cross nervure in the lower basal cell of the- 



fore or hind wings. (30.) 

 Only one cross nervure in the lower basal cell of the fore 

 or hind wings. (52.) 



30. Ifo supratriangular nervures. (31.) 



One or more supratriangular nervures. (36.) 



31. Abdomen stout, or moderately stout. (32.) 

 Abdomen rather slender. (34.) 



32. Abdomen with segments 2-4 carinated *15. Perithemis. 



Abdomen with segments 2 and 3 carinated. (33.) 



33. Sectors of the arculus separated, or rising from a point 



or very short stalk *39. Leptetmm. 



Sectors of the arculus stalked *71. Cannaphilu. 



34. Abdomen hardly thickened at base ; last antenodal cross 



nervure on fore wings not continuous *53. Hemisiigma. 



Abdomen thickened or inflated at base; last antenodal 

 cross nervure on fore wings continuous. (35.) 



35. Triangle of hind wings with base placed far beyond the 



level of the arculus *48. Agrionoptera. 



Triangle of hind wings with base nearly coinciding with 



the arculus 56. Miscu/Aa. 



Para. 

 America. 

 E. Lidies. 



E. Indies. 



Madagascar. 

 Australia. 



S. America. 



Amboina. 

 E. Indies. 



Europe, Asia, Ame- 

 rica. 

 Haiti, Jamaica. 



Africa. 



East Indies. 



Para. 



2q2 



