The Imago. 59 



[Genuh Sympetrum.] 



A. Lejjs yellowish. 



a. Dorsal surface of abdomen of male vermilion, 

 often not well developed, with yellow spots 

 near the hinder margin of segments ; female 

 brown ; largest species iiriolatiiiii. 



h. Dorsal surface of abdomen of male briglit 

 crimson ; nervures of wings crimson in lioth 

 sexes foiiscolo>nhii. 



c. Dorsal surface of abdomen of male dull 

 red ; basal third of wing (more ox less) 

 deep saffron in both sexes flaveoluni. 



B. Legs black ; abdomen dilated towards extremity. 



a. Abdomen of male crimson sauguincuni. 



h. Adult male almost entirely black ; a yellow 

 tleur-de-lys on ventral surface of meta- 

 thorax in both sexes scoticiiin. 



[Genus Libellula.] 



A. Wings without black spots at node; abdo- 



men of adult male blue. 



a. An oblong dark patch at base of fore- 

 wings, and a triangular one at base of 

 hinil-wings depressa. 



h. Two dark lines at base of fore-wings, and 

 a dark line and smaller triangle at base 

 of hind-wings fuh'a. 



B. AVings with a black spot at the node . . . . quadriiiiaculata. 



[Genus Orthetrum.] 



A. Smaller species ; pterostigma yellow ; wings of 



female often yellow towards costa ; abdo- 

 men of male all blue ccvrulescens. 



B. Larger species; pterostigma black; wings 



hyaline; last four segments of abdomen of 



male more or less black cancellatum. 



[Genus Somatochlora.] 



A. Superior anal appendages of male not angled 



at middle, with two teeth below (Fig. 27). metal /tea. 



