Some Palaearctic species of Cordulegaster. 275 



tooth bent towards the base ; the margin is then dilated more or 

 less and slightly emarginate before the point. 



Inferior appendage one-third shorter than the superior, almost 

 quadrate, broader than long, a little notched at the end, the lateral 

 margins swollen, turned up at the extremity and pointed. 



Legs all black. 



Wings hyaline, often a little darkened. Neuration black, costa 

 yellow externally; pterostigma long, slender, black, surmounting 

 nearly 4 cellules; membranule rather large long whitish; anal 

 margin little excavated, the angle nearly right-angled. Triangle of 

 the 4 wings divided by a nervule ; internal triangle free ; 18-21 ante- 

 nodals in the superior; 13-15 in the inferior; 13-15 post-nodals in 

 both pairs. 



$. Resembles the (^ in colour, even in the labrum; but the 

 abdomen is less constricted in the middle and the oreillettes very 

 rudimentary. 



The vulvar margin is prolonged in two chitinous laminae, sur- 

 passing the end of the abdomen by more than 3 mm. They arise at 

 the base of segment 9, are contiguous, are hollow internally, and finish 

 in a point simulating the lower mandible of a Motacilla ; they are 

 applied against the underside of the abdomen, of which they support 

 segments 9 and 10, which are in some degree soft, their dorsal part 

 being of a nature much less hard than that of the other segments. 

 The base of each of these laminae is marked by a rounded yellow spot 

 which in dried examples becomes often brown. Segment 10 is often 

 marked with yellow on the sides. 



The anal appendages, one-third shorter than the last segment, are 

 slender, cylindrical, brown, with a sharp black point, separated by 

 strong protuberance, brown, hairy, which terminates the abdomen. 



Pterostigma longer, brown, surmounting 5-6 cellules. 



(After de Selys, Mon. des Gomphmes, pp. 593-5 



The principal characters may be summarised thus — 



(^. Frons yellow with a transverse frontal line of variable breadth ; 

 nasus yellow margined with black anteriorly; rhinarium black; 



