INDIAN DRAGONFLIES. 929 



to the bridge ; relation of trigone in hindwing to hypertrigone about a 

 a right angle ; trigone in the hindwing entire ; hypertrigone in the fore- 

 wing generally traversed, that of the hind usually entire ; 4th nervure with 

 only a slight undulation, its end bent abruptly towards the termen ; 1 to 2 

 rows of cells between 5 and .5« ; the discoidal field more or less contracted 

 at the termen and filled with 3 to 5 rows of cells ; anal iield of the 

 hindwing very broad ; the midrib of the loop nearly straight, its angula- 

 tion commencing very near the trigone so that the end segment, or toe of 

 the loop is relatively long, its outer angle broad and filled with numerous 

 cells, the space between the midrib and inner border very narrow ; the 

 space lying between the loop and anal border of wing filled with numerous 

 rows of narrow cells arranged transversely. Membrane moderately large. 

 Stigma short. 



Sexual organs : male : lamina broad and depressed at the base, the border 

 rounded and projecting ; tentaculte small, the internal backwardly curving, 

 robust hooks, the external small and angular ; lobe small and narrow. 



Female : borders of the Sth segment not dilated ; 8th ventral plate pro- 

 longed into a small, projecting vulvar scale ; 9th ventral plate broad, 

 carinated at the end, not overlapping the 10th ventral plate, 10th very 

 small. 



Key to Species. 



Wings marked with black and yellow. 

 At least 2 rows of cells between 5 and 5a. 

 i. Sexual diflerentiation very marked. 



Male with the whole of wings, suffused 

 with yellow. Fore wing with spots at the 

 node, trigone and at the middles of 6 and 

 5a, and 7 and 7a. Hindwing similar but 

 with two additional, transverse, basal bands. 

 Female with broader and shorter wings 

 than the m.ale, all apices of wings hyaline, 

 much more so in the fore than hind wingf, 

 the black markings more extensive than in 

 the male and the spots coalesced to form 

 broad fasciie which traverse the wing from 

 costa to termen . . . . . . . . R. varief/ata. 



ii. Sexual differences both in shape and colour, 



less marked. 



Male with apices of all wings tipped with 

 brown. In the forewing usually only a well 

 marked, black spot at the node, but often a 

 poorly marked, diffuse spot over the middle 

 of 5 and 5a and possibly a similar spot at the 

 trigone. In the hindwing similar spots, a 

 ray in the intercostal space at the base, and 

 two transverse, basal f ascise which are not as 

 extensive as in varier/ata. 



Female similar to male, but the marks usually 

 more extensive or better marked. Apices 

 of all wings tipped with brownish black .. R. phyllisphyllis. 

 II. Wings marked with black only. 



At least 2 rows of cells between 5 and 5«. Wings 



entirely black with a metallic lustre, except 



the extreme apices which are hyaline. . . R. plutonia 



