I 



INDIAN DRAGONFLIES. 501 



2 rows of cells in its proximal part or 1 row of 3 cells at the trigone, followed 

 by rows of 2, strongly dilated at the termen ; anal field of hindwing broad, 

 2—3 rows of cells between the inner border of the loop and the basal raargin 

 of wing ; loop with a right-angled outer angle and with bifurcated cells. 



Membrane and stigma of medium size. 



Abdomen slim and nearly cylindrical in both sexes, dilated at the base and 

 dorso-ventrally in the distal half of the 7th and for the whole of the 8th and 

 9th. 



Sexual organs : For those of the male see under species. 



Of the female ; border of 8th segment not dilated ; 8th ventral plate at its 

 end prolonged into a projecting and somewhat bipartite, vulvar scale ; 9th 

 ventral plate flat at the base or slightly keeled and furnished with small 

 hooks, the apical half usually somewhat bent ventralwards and the end pro- 

 longed as a tongue-like projection overlapping the 10th segment. 



Key to Species. 



A. Trigone in the forewing free. 



Subtrigone in the forewing free, (rarely 

 formed of 3 cells.) 



Discoidal field With 2 rows of cells at its com- 

 mencement D. nehvlosa. 



B. Trigone in the forewing traversed, (rarely one or 



both free.) 



Subtrigone in the forewing formed of 3 cells. 



Discoidal field commencing with 3 cells and 

 then continued as 2 rows of cells (rarely 

 commencing with 2 cells) D. trivialis, 



37. Diplacodes nebuiosa, Kirby, Trans. Zoo. Soc. Lond. 12, p. 308. (1889). 



Karsch and Selys. 

 Kirby, Cat. p. 42, 1890. 



Id., Linn., Soc. Journ. Zool, 24. p. 556, 1893. 

 Diplax nebuiosa, Brauer, Zool. hot. Wein. 18. p. 721, 1868. 



Selys. Ann. Soc. Ent. Belg. 27 p. 96. 1883. 

 Libellula nebuiosa, Fabr. Ent. sys. 2 p. 379, (1793). 



Hagen. Zool bot. Wien. 8 p. 481. 1858. 

 Expanse 42 mm. Length 24 mm. 



Male : in adults and usually in moderately juvenile specimens, the whole of 

 the thorax and abdomen is black, frosted finely with blue and the markings 

 almost or entirely obsolete. The head black, the forehead and upper part of 

 epistome being highly glazed and of a bluish lustre. The labrum brownish ; 

 the eyes deep sea blue, paler beneath. Legs black. 



Juvenile specimens : head ; forehead, epistome, labrum and labium pale 

 yellow; a fine dark line to forehead in front of the vesicle which is bright yellow ; 

 occiput bright yellow ; eyes pale blue beneath, brownish above. 



Prothorax pale' yellow, the brown humeral band of the thorax continued 

 on to it. 



Thorax ; dorsum broadly black, 2 yellow spots at the wing attachments, a 

 narrow, diffuse, humeral band which uniting with the mid-dorsal dark area, 

 encloses a variably sized spot of yellow. The sides bright yellow, the sutures 

 mapped out in black, an interrupted black line over the spiracle, the metepi- 

 meron variably black. Often there is a very variable marbling of brown on the 

 sides. 



Legs yellow, black on the flexor surfaces. 



