The Imago. . 6i 



B. More blender species ; wings smaller ; anal ap- 

 pendages of male (Fig. 39); black spot on 

 dorsal surface of tir.st segment of female 

 semi-elliptical (Fig. 40, ^'.) sponsa. 



[Genu-- Pyrrhosoma-] 



A. Species large and bulky; front of thorax with 



two crimson strijies ; abdomen of male 



partly bronze nymphiila. 



B. Species smaller and more slender ; front of 



thorax willmut lines (or extremely fine 

 yellow ones) ; abdomen of male entirely 

 crimson ; abdomen <if female crimson on 

 the first, second, and third segments only., tenelhtiii. 



[Genus Ischnura.] 



A. Species small ; black, with ninth and jiart of 



eighth segments blue in male, not in female ; 



hind lobe of prothorax rounded, raised . . puuiilio. 



B. Larger species; black, with eighth segment 



entirely blue (ninth black) in both sexes ; 



hind lobe of prothorax narrow, much raised elegnns. 



[Genus Agrion.] 



.V. Male with a U-shaped black mark on dorsal 

 surface of second segment of abdomen, mark 

 joined to the black circlet behind ; female 

 blue and black, resembling male pidchtllitm. 



B. 2^Iale with a U-shaped black mark on second 



segment, not attached to the circlet ; 

 lemale abdomen black - bron/.e, except 

 yellowish circlets pitcUa. 



C. Male with lilack :Mercury sign (Plate XXVI., n.) 



— a circle with two horns in front and a 

 stem behind joining it to circlet — on second 

 segment ; female abdomen black- bronze, 

 with two blue circlets near extremity . . merciiriale. 



[Genus Enallagma.] 



A. ^Male with a black ellipse, generally joined to 

 the circlet on the second segment ; female 

 abdomen green or blue, with a large conical 

 black spot on most segments, but leaving 

 a fair amount of frround-colour between . . cvafliis;enim. 



