€10 JOURNAL, BOMBAY NATURAL HIST, SOCIETY, Vol. XXV. 



Ear-shaped processes on 2nd abdominal segment 

 jibsent. 



The male generally with poorly developed and differ- 

 entiated anal appendages. 



Very marked differentiation in the sexual organs of 

 the 2nd abdominal segment. 



Only occasionally species coloured metallic Libellulince. 



A small, triangular or arched, circumscribed projection 

 at the middle of the hind border of each eye 



Anal border of the hind-wing notched in the male. 



Nearly always a tuft of small hairs at the distal end of 

 the anterior femorte. 



A small ear-shaped process at the sides of the 2nd 

 abdominal segment in the males. (Very poorly marked in 

 the Hemicordtdia). 



The male with robust, small appendages. 



Considerable differentiation in the sexual organs on 

 the 2nd abdominal segment. 



Usually bright metallic coloured species . . . . Cordulince. 



Key to Sub-families of the Aeschnid.e. 



Eyes broadly contiguous. 



Vesicle prominent. (In the Petalia group the eyes 

 only just touching and the vesicle very small). 



The trigone in both pairs of wings nearly identical, 

 vf ry considerably elongated in the long axis of the wing. 



Subcostal space free or traversed, cubital space with 

 numerous uervures and only slightly differentiated. 



A right-angled svibtrigone in both wings. 



Female with an ovipositor lying between a pair of val- 

 vular scales on ventral surface of the 9th abdominal 

 aegment. 



Middle lobe of labium whole or with a flat, compress- 

 ed, oval process terminating in a small swollen border. 

 (Deeply notched in the Petalia group). 



Larva : labium flat, the lateral lobe similar to the 

 Gomphinte ; no mental bristles. Antennse slim, 7-jointed, 

 robust . . . . . . . . . . . . . . . . AeschniTKB. 



Eyes separated by abroad space, the interval sharply 

 edged posteriorly and considerably more narrow than 

 the diameter of the eyes as seen from above. 



The ocelli lying free or partially overhung by a pro- 

 minent ridge whose shape, in the group approaches that 

 of a vesicle. 



In shape the trigone of fore and hind-wings is con- 

 stantly slightly dift'erentiated so that the trigone of the 

 hind-wing appears somewhat elongated in the length of 

 the wing ; in the fore-wing, generally the costal and 

 proximal sides of the trigone of uniform length. 



Subcostal space always free of uervures and only a few 

 in the cubital space. 



Subtrigono in both fore-and hind-wings. 



Female with a divided vulvar scale at the moditied 

 border of 8th ventral plate. 



Middle lobe of labium whole. 



