INDIAN DRAGON FLIES. 145 



Protborax lobe very small, spherical, slightly convex, not projecting. 

 Thorax robust. 



Lews moderately short ; hind femorte with a few widely distant, gradu- 

 ally lengthening spines ; tibial spines moderately numerous, short and 

 slim ; claw-hooks ordinary . 

 Genital organs, : (see species). 



Wino-s long and moderately narrow ; reticulation close ; trigone in the 

 forewino- a little distal to the trigone in the hind ; sectors of the arc in 

 forewino- short, in the hind moderately long ; site of arc a little variable, 

 generally between the 2nd and 3rd antenodal nervures, often at the 2nd, 

 rarely between the 1st and 2nd ; 8th nervure in the hindwing at the tri- 

 gonal angle ; antenodal nervures llAtol6^ (in seven consecutive specimens 

 examined, these numbered 11^, 12i, 13^, 11|, 15|, 1-1 and 14i.) ; base of 

 trigone in the hindwing at the arc ; the outer side of the latter trigone 

 concave ; 1 cubital nervure to all wings; no supernumerarj'- nervures to the 

 Bridge ; trio-one in the forewing moderately narrow, at a little more than 

 a right angle in relation to the hypertrigone ; all trigones traversed ; all 

 hypertrigones entire ; 4th nervure with a strong double curve at its middle; 

 the discoidal field with nearly parallel borders, but slightly dilated at the 

 termen with 3 rows of cells ; 2 rows of cells between 5 and .5« ; anal field in 

 forewino- with 2 to 3 rows of cells, in the hind, wide and with a well-deve- 

 loped loop, the outer angle of which is nearly right-angled and extends 

 about 2 cells breadth distal to the apex of the trigone. 



Stigma large and narrow. Membrane large white or greyish. 

 9. Potamarcha obscura, Karsch. 

 Liheltula ohscuva, Ifambur. 

 Orthetrum obscura, Kirby. 

 Libellula conf/ener, Rambur. 

 Orthetrum cmifjener, Brauer. 

 Potamarcha conrjener, Selys. 



Expanse 68 mm. Length 45 mm. 

 Head : eyes brown above, laterally and beneath a slatey, opalescent blue ; 

 occiput small, dark brown; vesicle dark brown; front, epistome and 

 labrum a dirty, creamy white ; labium yellow. 



Protorax : black ; in the male heavily frosted with white and so appearing 

 blue; in the female a dark brown, with a mid-dorsal, bright yellow stripe, 

 bisected with a line black line. 



Thorax ; male black heavily frosted over with white and so appearing 

 blue. The colouring varying greatly according to the age of specimens 

 and also according to the season in which they are taken. Juvenile spe- 

 cimens and wet season forms bear, to a greater or lesser extent, the yellow 

 markings of the female described below. A complete series may be 

 taken showing from an intense white frosting with no markings, up to 

 others which have little or no white powdering and approach the females 

 in the richness of their colouring. Female : a deep chestnut brown or 

 black with no white frosting and marked with yellow or greenish-yellow as 

 follows :^the mid-dorsal line on the prothorax continued on to the thorax 

 as far as the tergum, the fine black line bisecting it as on the prothorax, 

 laterally the whole of the side bright yellow, with three, oblique, narrow, 

 black streaks traversing it, the anterior and posterior of which are bisected 

 above to form two large, Y-shaped marks. 



Wings hyaline, the apices slightly tinted with brown, in the male ; 

 the area between the node and the stigma is occasionally faintly smoky ; 

 in the female, the area from base to stigma, anterior to the 3rd nervure is, 

 especially in the wet season forms, more or less suflused with amber tinting. 

 Abdomen: ventro-dorsally dilated at the base ; the sides parallel as far as 

 the 8th segment from where it tapers to a point at the anal end, a little 



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