The Odonafa or Dragoiiflies of SonfJi Africa. 297 



tlie posterior lobe fits into this concavity as a trapezoid process, very 

 slightly narrower posteriorly ; on this lobe a transverse anterior 

 ridge, almost vertical and rather high, cut in a straight line with 

 slightly projecting lateral ends ; further, two lateral longitudinal 

 ridges, low anteriorly, rising at the posterior end, arched on lateral 

 view. The posterior, nearly straight edge of this lobe fits on the 

 mesothorax into a groove between two narrowly triangular, transverse 

 mesostigmal laminae. 



Thorax ferruginous, gradually shading into lighter tints laterally 

 and posteriorly; a blackish dot in the dorsal end of humeral suture; 

 a very narrow black line on dorsal edge of mesepimeron ; black dots 

 on anterior and posterior dorsal end of metepiuierou. 



Legs long and robust. Spines of femora aud tibiae long, fine and 

 very numerous, about 15 on each side of third femora, 12 on third 

 tibiae. Tooth of claws robust near the point. Legs light yellowish 

 brown, internal side of tibiae, tarsi and spines black. 



Abdomen comparatively robust, dull reddish brown ; terminal joints 

 of segments 1-7 narrowly blackish ; from 2-7 a narrow somewhat 

 diffuse dark longitudinal mid-dorsal line, widened into a fine trans- 

 verse line near the end of each segment. Posterior edge of tenth 

 segment with a small triangular notch, and a group of small blackish 

 spines on each side. Appendages very small, yellowish. Valvae 

 moderately long, the styloids just reaching the end of abdomen. 



Wings (Plate VII, fig. 10) light greyish yellow, from base to nodus 

 in costal half to distal end of quadrilateral in anal half deeper yellow. 

 Pterostigma whitish yellow, very opaque. 



Aid. 3-2, hdw. 28-5' mm. 



The male as described by de Si'lys and very probably also the adult 

 female must be very much darker insects. 



PSEUDAGRION (Si'lys, 1876). 



As originally defined by de Selys this genus embraces a large 

 number of species inhabiting the inter-tropical regions of the Old 

 World, a few of them extending beyond the limits of the tropics in 

 South Africa, in Australia, and along the frontier of the Palaearctic 

 region. Continental Africa appears as the chief centre of Pseiidagrion, 

 not, less than 24 species from this continent being known to the 

 writer. Unfortunately in the actual state of literature their identi- 

 fication is extremely difiicult ; nearly all existing descriptions are 

 given without the all-important figures of structural details, and 

 many of them are not comparative at all ; thus their condition may 



