342 BRITISH SPECIES [CH. 



lines. Abd. much swollen at 1 2, slightly constricted at 3, bright blue with 

 an irregular mid-dorsal black band. App. sup. 5, thickened in middle, inner 

 border curved, tips rounded; inf. 1-5, broad, truncated. $ very similar to c?, 

 but eyes and abd. greenish; apps. 5-5, leaf -like. Fairly common; Southern. 

 May Aug. 



Fig. 172. Wings of Anax imperator Leach, $ (Hw 46 mm.). Original. 



Family LIBELLULIDAE (Characters, p. 265). 



Subfamily Corduliinae (Characters, p. 265). 



Tribe Idocorduliini (Characters, p. 267). 



Genus VI. Oxygastra Selys (fig. 152). Fw with 2 rows of post-trigonal 

 cells. Al without a toe. Hw with a weak st ; t free in all wings. 



11. O. curtisi Dale. 3 abd 36 38, hw 33 36, pt 2. Bases of wings 

 slightly saffroned; C yellowish brown; memb. whitish. Eyes only slightly 

 touching. Colour metallic green ; abd. slightly clubbed, with long lanceolate 

 mid-dorsal yellow markings on 1 7 ; 10 with a compressed yellow piece project- 

 ing between apps. App. sup. short, subcylindrical, hairy, divergent ; inf. blunt, 

 slightly bifid. $ abd 3336, hw 3234, pt 2-5. Wings clouded with yellow. 

 Coloration as in <$ ; no projecting piece on 10 ; apps. short, conical. Very rare ; 

 Southern. June July. 



Tribe Eucorduliini (Characters, p. 267). 



Genus VII. Cordulia Leach (fig. 129). Fw with 2 rows of post-trigonal 

 cells, followed later by 3. No st in hw ; t crossed infw, free in hw ; memb. large. 

 Al with a distinct toe and a straight sole. App. inf. of $ forked. 



