TJie Odonata or Dragovflies of South Africa. 317 



the latter also relatively longer. The colours are rather coDspicuously 

 different fi-oni fully coloured, much less so from immature glahrum. 

 The female remains unknown. We must expect to find it difficult of 

 identification from the female of glabrum. 



ENALLAGMA (Sclys, 1876). 



This genus is chiefly North American ; it is represented in Europe 

 by a single species, in Africa by a group of closely allied forms which 

 are very imperfectly known. 



No sufficient reason can be found for seisarating this African group 

 generically from the main body of the genus, although geographical 

 reasons might suggest such a sejaaratiou. Two species not yet known 

 from within the limits of the present fauna are described here, as it 

 was found desirable to take notice of all the species known to the 

 writer from continental Africa. • 



Table of Males. 



1. Dorsum of tenth segment somewhat abruptly elevated in the middle, the 



projection divided by a narrow excision in two small rounded lobes. 

 Superior appendages directed caudad, with no medial ventral projection, 

 somewhat furcate in side view ; conspicuously longer than the inferior. 



Dorsum of tenth segment gradually (if at all) elevated in the middle with 

 a narrow triangular or broadly arched excision, not distinctly bilobed. 

 Superior appendages, see under 3 and 4 ...... 3. 



2. Two elevated, almost circular lobes at the ventral end of median thoracic 



suture. Pterostigma conspicuously longer than broad ; wings narrower 



than in following species E. suhfurcalum. 



No elevated lobes at the median thoracic suture. Pterostigma very 

 little longer than broad, wings comparatively broader than in swii- 

 furcatum (and other species here described) . . E. rotundipmne. 



3. Cuq nearer the level of first than of second Anq. Superior appendages 



shorter than tenth segment, directed caudad and very slightly ventral, 

 obtuse ; tenth segment very broadly and shallowly excised. Dorsum 

 of thorax and abdomen chiefly black . . . . E. nigridorsum 

 Cuq at equal distance from first and second Anq or nearer second . 4. 



4. Superior appendages directed caudad, roughly triangular in dorsal view, 



their medial border projecting ventrad nearly as long as tenth segment. 



5. 



Superior appendages bent strongly ventrad, at least in their basal half ; 



' no distinct medial ventral dilatation 8. 



5. Pale colours light ochreous, bluish only on terminal segments. Pterostigma 



and appendages very light yellowish . . . . . E. suhtile. 

 Pale colours blue. Pterostigma gi-eyish ochreous to black. Appendages 

 blue and black to almost black 6. 



