6o British Dragon-flies. 



B. Superior anal appendages of male angled at 

 middle like forceps of some earwigs, three 

 or four teeth below (Fig. 28) arctica. 



[Genus .^schna.] 



A. Abdomen nearly black, spotted with blue 



(generally yellowish in female) ; wings 

 hyaline. 



a. Eyes meeting but for a short space ; spots 



all blue, nearly obliterating ground-colour. ccEridea. 

 h. Eyes in contact for a long distance. 



1. Dorsal blue spots on segments 9 and 



10, divided in middle. 



(i.) Costa brown ; suture between 

 nasus and frons without 



black line mixta. 



(ii.) Costa golden; suture between 

 nasus and frons distinctly 

 black jiincea. 



2. Dorsal blue spots on segments q and 



10 united; two /arge oval yellowish- 

 green spots on front of thorax . . . . cyanea. 



B. Abdomen russet, but little spotted ; wings 



brown. 



a. Accessory membrane small, pale ; without 



mid-dorsal triangle on segment 2 . . . . graiidis. 



h. Accessory membrane large, black ; a bright 



yellow triangle on segment 2 isosceles. 



[Genus Calopteryx.] 



A. Wings of male almost entirely blue; of female 



brown ; pterostigma rather distant from 



tip of wing virgo. 



B. "Wings of male with a large blue patch only in 



centre ; of female greenish, pterostigma 



nearer tip of wing spleinieiis. 



[Genus Lestes.] 



A. Shorter and stouter species ; wings larger ; 

 anal appendages of males (Fig. 38) ; black 

 spot on dorsal surface of first segment of 

 female rectangular (Fig. 40, a.) dryas. 



