THE SUBFAMILY LIBELLULIN^. 



263 



81. Base of triangle of hind wings considerably beyond the 



level of the arciilus. (82.) 

 Base of triangle of hind wings nearly coinciding with the 

 arculus. (83.) 



82. Abdomen slender *48. Arjnonoptera. 



Abdomen stout 45. Jfesocria. 



83. Frontal tubercle bifid ; eyes merely touching in front .. *65. Orilietrum. 

 Frontal tubercle truncated ; eyes distinctly contiguous in 



front. (84.) 



84. Abdomen slender 63. Neoeysta. 



Abdomen stout *38. Orihemis. 



85. Basal segments of abdomen broad, terminal segments 



suddenly tapering 77. Acisoma. 



Abdomen more uniformly broad, often inflated at base, or 

 gradually tapering. (86.) 



86. Triangle of fore wings free. (87.) 

 Triangle of fore wings traversed. (96.) 



87. Fore wings with last antenodal cross nervure con- 



tinuous. (88.) 

 Fore wings with last antenodal cross nervure not con- 

 tinuous. (89.) 



88. Wings and pterostigma rather short 26. Microthemis. 



Wings and pterostigma rather long 27. Brachydiplax 



89. Fore wings with three or four rows of post-triangular 



cells. (90.) 

 Fore wings with two rows of post-triangular ceUs. (94.) 



90. Abdomen long and slender ; wings long *o3. Hemlstigma. 



Abdomen and wings rather short or moderately long; 



abdomen not remarkably slender. (91.) 



91. Abdomen with segments 2 and 3 carinated. (92.) 

 Abdomen with segments 2-4 carinated. (93.) 



92. Abdomen stout, hardly thickened at base *2.5. C'rocolhemis. 



Abdomen slender or moderately stout, generally distinctly 



thickened at base *20. Sympetrum. 



93. Subtriangular space consisting of three cells *24. Bi-achythemis. 



Subtriangular space consisting of one cell 72. Caeeryates. 



94. Triangle of fore wings long and narrow *75. Diplacodes. 



Triangle of fore wings broad. (95.) 



95. Triangle of hind wings with its base nearly coinciding 



with the arculus 51. Aiiatya. 



Triangle of hind wings with its base placed considerably 



beyond the arculus 50. Maphismia. 



96. Basal half of pterostigma pale *o3. ffemistigma. 



Basal half of pterostigma not paler than the rest. (97.) 



97. Fore wings with six continuous antenodal cross nervures . 70. Pachydiplax, 

 Front wings with the last antenodal cross nervure very 



rarely continuous, in cases when the total number 

 exceeds six. (98.) 



E. Indies. 



Solomon Islands. 

 Old Worid. 



8. America. 

 America. 



Africa, E. Indies. 



Papua, Borneo. 

 E. Indies. 



Africa. 



Old Worid. 



Cosmopolitan. 

 E. Indies. 

 Africa, W. Asia. 

 Africa, Asia. 



Brazil. 



Ceram. 

 Africa. 



N. America. 



