The Odoiiata or Draijonflies of South Africa. 319 



5. Thoracic dorsum each side with a blackish band along the median ochreous 



line ; each black band about as broad as the ochreous ante-humeral 

 strijje of the mesepisteruum. Pterostigma greyish ochreous . . 6. 

 Dark bauds of thoracic dorsum golden brown, only centrally darkened 

 to a narrow blackish line. Pterostigma pale yellow. Posterior lobe of 

 prothorax comparatively broad, regularly convex, slightly depressed in 

 the middle E. subtile. 



6. Smaller species. 1 abd. 2li, hJir. 19 mm. Hind lobe of prothorax compara- 



tively broad, regularly convex, slightly depressed ventrad in the middle. 



E./ractum. 

 Larger species. Abd. 2S'5, hdw. 20 to 3C, pt. 2'1 mm 7. 



7. Hind lobe of prothorax moderately broad, almost regularly convex at free 



margin, very slightly depressed in middle. Dorsal black band of abdomen 

 very narrow, light colour of sides largely visible in a dorsal view. 



E. si7iuatum. 

 Hind lobe of prothorax narrow at the sides, broader in medial third, 

 where it is depressed and dorsally concave. Dorsal black band of 

 abdomen broad, light colour of sides not visible in a dorsal view. 



E. elongatum. 



Enallagma subfurcatum (St'lys, 1876). 



Coll. E. B. Williamsou : 1 S, Salisbury, Maslionaland (iv . 1906, 

 G. A. K. Marshall). Coll. Ris : 1 (J, 1 ? , Eritrea (Kristeuseu) ; S ^ , 

 8 9 , Harrar, Abyssinia (id). 



(J . Occ'ijjut light blue, rather broadly bordered with black at the 

 forameu. Labium whitish. Dorsal surface of head light blue, 

 marked with black ; narrow line at base of labrum ; postclypeus entirely 

 black ; vertex from the base of antennae backward, interrupted by 

 cuneiform postocular spots and a narrow line on the occipital margin, 

 which are blue. Prothorax black, marked with blue ; narrow line 

 ou anterior margin interrupted in the middle, lateral borders and 

 small dorsolateral triangular spots. Posterior lobe black, narrow, 

 erect, in a low arc, from the vertex of which a small bluish point 

 projects horizontally backward. Thoracic dorsum black ; complete, 

 straight, blue ante-humeral lines, distant slightly more than their own 

 breadth from humeral suture. Humeral black colour extending 

 laterally to about half-way between humeral suture and the stigma, 

 somewhat irregular in posterior outline ; projecting jiosteriorly at the 

 ventral end, a narrow blue stripe cutting into the dorsal end obliquely 

 towards the humeral suture. Sides otherwise blue ; a black dot in 

 dorsal end of second lateral suture. Ventral side blue. Legs greyish 

 blue ; external side of femora and tibiae broadly black ; tarsi ochreous, 

 obscure at the joints. 



Abdomen moderately stout ; segments 1 to middle of 3 and 8 to 

 10 blue, middle of 3 to 7 dull yellowish or light olivaceous, marked 



