INDIAN DRAGONFLIES. 



166 



27 



Fig, 27. — a. Female genital organs of O, (jlaucum. b. Female genital 

 organs of O. tiicmcjulare. c. Male genital organs of O. 

 piuinosum. d. Male genital organs of O, trianyulare, 



Male : 



Head ; eyes just meeting, brown above, olivaceous and paler at the 

 sides and beneath ; vesicle prominent deeply notched, black ; face brown, 

 labriim and labium greenish yellow ; suture deep. 



Frothorax ; dark brown, the lobe furnished with a very long ruff of hairs. 



Thorax : a deep chestnut brown, almost black, laterally a bright greenish 

 yellow traversed by a broad brown stripe. The dark brown parts are den- 

 sely pubescent ; the yellow parts naked. 



Legs robust, black ; hind femorse with a row of stout ; gradually length- 

 ening spines; tlie mid-femor!B similar but the spines much less numerous. 



Claw-hooks robust, nearer base than apex. Tibial spines fairly numerous, 

 long and robust. 



Wines broad and lone ; arc between the 2nd and 3rd antenodal nervures 

 or at the 2nd ; sectors of arc short in the forewmg, longer in the hind; 

 trigone in the lorewing traversed once or twice, its proximal side somewhat 

 sinuous ; trigone in the hindwing traversed; its distal side concave ; hyper- 

 trigone in the forewing traversed, in the hind entire ; 15 to 17 antenodal 

 nervures ; the loop broad and long ; its mid-rib bent to nearly a right angle 

 and with split cells both at the trigone and at the outer angle; discoidal 

 field broadly dilated, with 3 rows of cells ; 8th nervnre at the anal angle of 

 the trigone in the hindwing ; 2 rows of cells between 5 and 5«. 



Stigma dark brown, large. Membrane dark grey. At the base of the hind- 

 wing a dark, opaque, blackjsh brown, triangular mark reaching in the superior 

 costal space to the 1st antenodal nervnre, in the inferior costal space to the 

 2nd, rather more than half-way over the sub-costal and cubital spaces and 

 from thence sloping gradually to about the middle of the membrane. Just 

 a suspicion of a brownish black mark in the forewing. 



Apices of wings faintly smoky. 



Abdomen, ventro-dorsally, dilated at the base, then markedly depressed 

 as far as the 7th segment, from which point to the anal end it is strongly 

 carinated. Markedly fusiform, the broadest part at the 4lh and nth seg- 

 ments ; 1st and 2nd segments^ deep mahogany brown, the 1st segment being 

 densely coated with h^ng hair, especially at the sides ; 3rd to 7th bright 

 cobalt blue; the remaining segments black. 



