TJic Imago. 57 



III.— Table of Genera. 



[Sub-Family Libellulix.i-:.] 



A. Triangular dark spot at base of hind-wings. 



a. Abdomen mid-dorsally spotted, sides parallel Leucorrhinia. 



b. Abdomen without mid-dorsal spots, sides 



not parallel Libellula. 



B. Wings unspotted. 



a. About seven ante-cubital ner^■ures ; adult 



male red or blaclc Sympetrum. 



h. About twelve ante-cubital nervures ; adult 



male with abdomen blue Orthetrum. 



[Sub-Family Cokdi'liixj:.] 



A. Abdomen without mid-dorsal spots. 



a. Inferior anal ap];)endage of male triangular Somatochlora. 

 h. Inferior anal appendage of male deeplv 



cleft Cordulia. 



B. Abdomen spotted mid-dorsally with yellow ; 



inferior anal appendage of male notched 

 only at hinder extremity ; superiors with a 

 long basal internal point Oxygastra. 



[Sub-Families GoxiPHiN.i; and Curdl'le- 



GASTERIN.E.] 



Each sub-family contains but one genus, and each 

 genus but one species, the ground-colour in each 

 case being black. 



a. Size moderate ; yellow marks longitudinal Gomphus. 



h. Size large ; yellow marks transverse . . . . Cordulegaster. 



[Sub-Family ^-EscHNix.i:.] 



A. Abdomen unspotted, but with a black, mid- 



dorsal jagged line on blue or green ground ; 

 anal angle of hind-wings of male rounded : 

 auricles absent ; pterostigma narrowish . . Anax, 



B. Abdomen spotted. 



a. Pterostigma very narrow indeed ; anal 

 angle of hind-wing of male very bluntly 

 pointed ; inferior anal appendage of male 

 lightly notched at tip Brachytron. 



