338 Annals of the South African Museum. 



Ante-nodal cross-veins predominantly not coincident in costal and sub- 

 costal space ; two of them always coincident and crossing the double 

 space as triangular membranis. Proximal anal border of hind wings 

 (^Jia* excepted) excised in males; lateral earlets on second abdominal 

 segment of males ........ Fam Aefchnidae. 



Ca. Eyes sejjarated by a large space (Text fig. 2). Ocelli free or only partly 

 covei-ed liy a transverse ridge. 



Costal side of triangle not exceeding considerably in length the proximal 

 side. No radial supplement parallel to vein Rs. Female genital opening 

 covered by a vulvar scale. Inferior appendage of male bifid 



Subfam. Gomiihinae. 



Cb. Eyes contiguous in tlie median line for a considerable space. Ocelli 

 situated at the foot of a frontal vesicle. Costal and anal side of triangle 

 considerably exceeding the proximal side in lengtli. A radial supple- 

 ment roughly parallel to vein Rs. Female genital opening armed with 

 an ovipositor in the manner of Zijgoplera. Inferior appendage of male 

 not bifid ......... Subfam. Acschninae. 



D. Lateral lobes of labium, very large, touching each other in the median line 

 to form a mask-like structure ; median lobe very small ; no second joint 

 to the lateral lobes (Text-fig. l!). Triangles dissimilar in both pairs of 

 wings ; their longer axis in the short transveise axis in the front wing, 

 in the long axis in the liind wing ; vei'y ol ten dissimilar also in position ; 

 distal to the arciilus in front wing, at the arculus in hind wing. Ante- 

 nodjil cross-veins coincident in costal and subcostal space (except in 

 many cases the last one, which remains limited to costal space) ; all of 

 them equal in structiue. Females with vulvar scale. Inferior appendages 

 of males not bifid Fam. Libelhdidae. 



Da. Proximal anal border of hind wings excised in males ; lateral earlets on 

 second abdominal segment of males. A small projection at the occipito- 

 temporal border of eyes in both texes. Mostly metallic colours on body 



Subfam. Cordulinae. 



Db. Proximal anal border of hind wings rounded in both sexes ; no earlets on 

 second abdominal segment. 



No distinct projection (indicated in Urothcmis) at the occipito-tempor..l 

 border of ej'es. Colour system mostly not metallic 



Subfam. LibelluUntie. 



II Ca. Si:biamilv GOMPHINAE. 



Goiiqihinae are a very hoiuogeueous lot throughout the world iu 

 the superficial (thouo;h probalily phylogeuetically very iniportaut) 

 character of colour system. Their numerous species show an iufinite 

 variation of a pattern of black and yellow, the black parts of which 

 may pass through many shades of browu to light ferruginous or 

 greyish ochreous in the palest forms, whereas the yellow parts may 

 pass to orange or through various shades of olivaceous to pure green, 

 verv rarely to blue. 



