392 Annals of Hie Soittli African Museum. 



more anterior segments in immature specimens). Female with face and 

 frons dull olivaceous, a narrow medially interrupted black basal line of 

 frons. Thorax olivaceous, sides yellowish ; light yellowish mid-dorsal 

 longitudinal hand from prothorax to inter- alar space ; one or two in- 

 complete dark lines each side between this band and humei'al suture. 

 Abdomen dull ochreous ; continuous, more rarely interrupted, lateral 

 black bands from segments 2 to 10, distant from lateral carina not fully 

 by its own breadth. Tips of wings brown to distal end of pterostigma. 

 $ , Aid. 28, Juln\ 33, pt. < 4 mm. ? , 27, 30, 4 . . . O.farinosum. 



2. Ante-nodal cross-veins in sub costal space ochreous or whitish. Pterostigma 



light coloured .... ...... 3. 



Ante-nodal cross-veins in sub-costal space black. Pterostigma of mature 

 specimens very dark ferruginous or almost black. Membranule black. 

 Basal spot in base of sub-costal and cubito-anal space and along mem- 

 branule, golden yellow to brown in male, lighter yellow in female. 

 Thoracic pattern of non-pruinose males two dorsal and five lateral 

 about equally developed black stripes on uniformly greenish ground, of 

 females similar, but with reduction of black area, especially at the sides. 

 Abdominal pattern of non-pruinose males transverse median ochreous 

 or olivaceous bands on segments 4-G, very variable in extent ; similar in 

 females, but with light-coloured area more extended, especially along 

 mid-dorsal line; terminal abdominal segments wholly black in mature 

 specimens of both sexes. Males pruinose blue first on abdomen, later on 

 thorax, leading in some very mature specimens to the disappearance of 

 every trace of pattern. Frons greyish olivaceous, darker in male, with 

 basal black line, broader in male, narrow in female. $ , Aid. 28, hdiu. 32, 

 pt. < 3 mm. <j> , 29, 32, 3 . O. stemmale capense. 



3. Abdominal pattern in non-pruinose males and in females a mid-dorsal 



longitudinal black band, widened at the joints. Pterostigma large. Cu l 

 in hind Aving regularly separated from anal angle of t . . .4. 

 No mid-doi-sal longitudinal black band on abdomen. Cu { in hind wing- 

 but occasionally separated from anal angle of t . . . .5. 



4. Large species. Wings hyaline at base. Pterostigma very light yellow, 



almost whitish. Lips, face and frons greenish white ; nan-ow basal black 

 line on frons. Thorax olivaceous dorsally, light greenish at sides ; median 

 and incomplete antehumeral stripes fuscous, narrow black lines in 

 humeral and second lateral sutures. On abdomen besides mid-dorsal 

 also lateral black bands, narrowed or almost interrupted in median 

 third of each segment. 



Female with foliaceous dilatations of segment 8 very narrow and appen- 

 dages comparatively long. Mature males pruinose on abdomen to the 

 disappearance of pattern, less densely on thorax. $ $ , Abd. 36, hdw. 34, 



pt. 3'5 mm 0. trinacria. 



Smaller species. Wings in male hyaline or with golden yellow spot at 

 base, in female with golden yellow spot of various extent, sometimes to 

 level of Cuq and apex of membranule. Pterostigma bright ochreous. 

 Labium yellow with median black band ; face and frons yellowish ; 

 broad basal black band on frons and sometimes more black on anterior 



