144 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXVI 



Wings : base always hyaline, the apex smoky or greyish brown, and in 

 some species the whole wing smoky. The neuration more constant than 

 in acigastra ; the discoid al field of forewing strongly dilated at the termen; 

 arc situated at the 2nd antenodal nervure or beyond it, and occasionally 

 as far distal as the third ; 8th nervure strongly convex ; 4th and 5th 

 nervure strongly bent towards the termen. In the males, generally 

 only 1 row of cells between 5 and 5a ; in the females a row of double cells. 



Size very variable and the wings often showing asymmetry. 



Genital organs of the male : the lamina lying very low, the tentaculse very 

 large and prominent, shaped as an arched cone, with a somewhat sinuous 

 surface, generally meeting at, or actually crossing each other in the middle 

 line ; the lobe long and narrow, right-angled, a little dilated at the end and 

 cut straight away below, coated with long, stiff hairs, and rather more than 

 half the height of the tentaculfe. 



Female genital organs : lateral borders of the 8th abdominal segment 

 not dilated ; the 8th ventral plate separated from the vulvar scale by a 

 narrow margin ; the vulvar scale very small and bisected by a triangular 

 notch nearly up to its base ; 9th ventral plate prominently keeled and not 

 prolonged posteriorly. 



Hab. Burma. 



Ris mentions a male specimen in the British Museum from Col. Bing- 

 ham, Burma, which he places provisionally as " cleis.'- Its body is frosted 

 white ; there is only 1 cubital nervure to the forewing ; 3 cubital nervures 

 in the hind ; the wings relatively narrower than in other specimens of 

 cleis, but the discoidal field shaped as in this species ; bright yellow, basal 

 rays to both wings ; a flattened hook on the inner border of the tentaculae. 

 Abdomen 32 mm. 



Hab. Bhamo. 



Hindwing 38 mm. 



Stigma 2 mm. 



Genus — Potomarcha. 



Fig. 19.— Wings of Potomarcha (x2). 



Potomarcha, Karsch. 



Libellula, Rambur. 



Orthetrum, Kirby and Brauer. 



Head moderately large ; eyes broadly contiguous, for about as long an 

 extent as the breadth of the occipital triangle : forehead flatly arched and 

 without a distinct foreborder , suture moderately deep ; vesicle high, nar- 

 row and notched. 



