2< 



BY R. J. TILLYARD. 449 



/'Inferior sector of triangle of foreivings reaching 

 jaH beyond basal postcostal nervule; inferior 

 appendages of male much longer than superiors. XaiUhocnemis, n.g. 



Inferior sector of triangle of forewinga normal; 

 inferior appendages of male either shorter, <»r 

 very little longer, than superiors 3. 



Snperior appendages of male forked or hollowed at 

 tips;* prothorax of female with two hooks point- 

 ing forward Pseudagrion. 



Superior appendagesof male not forked or hollowed; 



prothorax of female simple 4. 



(Superior appendages of male longer than inferior; 

 small species of blue and bronze colour Awtroagrion. 

 Superior appendages of male slightly shorter than 

 inferior; medium species of red colour Ceriagrion.. 



(iroup iv. Telebasis. 



'Inferior sector of triangle reaching the basal post- 

 costal nervule 1. 



Inferior sector of triangle not reaching the basal 



postcostal nervule Telebasis. 



Inferior tooth of tarsal claw present but very 

 small; female with a ventral apical spine on sog- 

 ment 8 Aciayrion. 



Inferior tooth of tarsal claw absent; female with- 

 out spine on segment 8 Stenohasis. 



Xanthoc7iemis connects Group iii. with Group ii. Aciayrion 

 connects Group iv. with Group iii. In Group ii., the last four 

 genera may be regarded as a strongly astheiiogenetic branch of 

 the main stem, connected to Agrion and Ischnura via Frosagrion. 



21. Agrion lyelli, n.sp.(Plate xlix., figs.l, 2, 20j. 



^. Total length 29, abdomen 23, hindtving 16 mm. 



Wings: neuration fine, black; ptei'ostigma 0-5 mm., black, 

 rhomboidal; post7iodals 10-12 on fore, 8-10 on hind wing. Head: 

 eyes dark violet above shading to pale blue beneath; epicranium 

 black, a transverse pale blue line in front reaching on to the 

 eyes; postocidar spots deep rich blue, connected by a fine blue 

 line; postclypeus black, anteclypeus and labrum pale blue, labium 



* Except in Ph. j</m'/e»- Tillyard, which is retained in this genus on its 

 venational and other characters. 



