INDIAN DRAGONFLIES. 741 



loop very loug and its apex bent sharply at a right angle to the stem, the 

 mid-nerviire bent at a ftght angle ; 2 or 3 rows of cells between the loop 

 and anal border of wing. Membrane of medium size. Stigma long 

 narrow. 



Sexual organs. See under species. 



Key to Species. 



A, Only 1 cubital nervure in the forewings. Trigones 



in both wings entire. Costal and proximal sides 



of trigone iu the forewing equal . , . . . . Z. ilia. 



B. 2 or o cubital nervures in the forewings. Trigones 



traversed or entire. Costal side of trigone in the 

 forewing much shorter than the proximal. 



a. 2 rows of discoidal cells as far as bridge . . Z. ida. 



b. 3 rows of discoidal cells at beginning . . Z. iris. 



Of the above 3 species, only iris is taken within Indian limits, the others 

 inhabiting Malaysia and Indo-China. 



55. Z. iris, Selys, 1869, Kirby, 1890, Martin, 1904, Ris, 1911. 



Zygonidia insignis, Kirby, 1900. 

 Zijgonidia malaijana, Laidlaw, 1902. 

 Zygonidia ceijlanica. Kirby, 1905. 

 Zygonidia cenea, Kirby, 1905. 



Male: Expanse 95 mm. Length 55 mm. Abdomen 38 mm. Hind wing 

 43 mm. 



Head : eyes deep sea blue above, paler beneath ; vesicle, forehead and 

 upper part of frons a shiny, metallic violet ; lower part of frons and epistome 

 bright yellow with an obscure black spot in the middle of latter ; labium 

 black with 2 small yellow spots at its base ; labrum yellow, its free border 

 narrowly black ; occiput black. 



Prothorax black marked with a fine, yellow collar anteriorly and a 

 similar one across the middle lobe. 



Thorax metallic green or bluey green, marked with yellow as follows : — 

 an irregular, broad, yellow post-humeral fascia, 2 broad, lateral, yellow 

 stripes, one at the spiracle and the other crossing the metepimeron, a row 

 of yellow spots on the tergum. The mid-dorsal cai'ina finely pale. 



Legs black, the anterior femora yellow beneath. 



Abdomen black, the first 3 segments shiny and sometimes with a 

 metallic lustre, the remainder a matt black. Segments 1 to 3 and the 

 base of the 4th with a large, lateral, yellow spot, the intersegmental nodes 

 as far as the 6th finely ringed with yellow, the dorsal carina finely yellow, 

 expanding on the anterior half of the 7th to form a large, yellow shield- 

 like spot. Anal appendages and the last 3 segments black, the former 

 being long and slim, as long as the 9th segment. 



Wings hyaline but faintly tinged with yellow, the apices distinctly 

 smoky. Stigma long, narrow, black. Membrane grey, the wing mem- 

 brane adjacent to it, narrowly brown. Neuration subject to much varia- 

 tion, even in the wings of any single specimen, asymmetry being the rule 

 rather than the exception. 



In one specimen, a male, there are 2 rows of cells between 5 and 5a in 

 the left forewing, 1 row in the right forewing ; in the right hind several 

 cells are divided and in the left, some are forked so as to form triangular 

 cells; antenoclal nervures in the left forewing 13i, in the right 15; in 

 another specimen, a female, the left fore and hind-wings have only 1 row of 



