608 



INDIAN DRAGONFLIES. 



BY 



Capt. F. C. Frasei{, LM.S. 



(With 5 Text-jhjv/i'es) 



(Contimied from ])age 471 of Volume XXV) 



Part II. 



Order— Odonata, Fabricius. 



Imago large sized, carnivorous ; biting mouth-parts ; reduced, bristle- 

 like auteunie. Very large, facetted eyes : 3 accessory eyes (ocelli). Thorax 

 bulky and composed of three parts — the prothorax, small, variable and 

 separate which bears the fore-legs ; the meso — and the meta — thorax fused 

 together, complexly built, flattened above and in front, and below and 

 behind, the former bearing the mid-legs and the fore-wings, the latter the- 

 hind-legs and the hind-wings. The legs made up of the usual parts, never 

 used for walking, held forward when the insect is flying to assist the jaws 

 in catching their prey. The wings four in number, all uniform in th«ir es- 

 sential characters, never folded when at rest, with long, straight or curved 

 nervures and a system of secondary, finer nervures. 



The costa and subcostal nervures joined at about the middle of the whigs 

 by a stout, transverse nervure (the " node "), 10 complete abdominal 

 segments ; the ventral plates narrow, folded under the overlapping borders 

 of the abdomen. Genital orifice of the male (primary sexual organs) on 

 ventral side of the 9th abdominal segment ; secondary sexual organs of 

 the male on the ventral side of the 2nd abdominal segment. The female 

 sexual organs between the 8th and 9th abdominal segments, llespiratory 

 organs, 4 thoracic spiracles and a pleural membrane and abdominal spira- 

 cles on the under surface of the abdomen. 



Larva ; similar to the imago in its essential characters ; aquatic, 

 carnivorous, without any resting stage (pupation). Labium with a pro- 

 longed chin (" mask") which is capable of snapping in and out. Antennie 

 similar to the imago. The facetted eyes as in the imago but smaller and 

 in a less developed form. Ocelli generally more or less obsolete ; wings 

 gradually developing in successive instars, in the final stage showing 

 almost the complete reticulation of the imago, liespiratory organs either 

 caudal or rectal. 



The Dragonflies split up naturally into two large suborders, the Anisop- 

 tera and the Zygoptera, which are differentiated by several important 

 characters of which the principal is the difference in shape of the fore and 

 hind-wings in the former and the uniform character of the wings in the 

 latter. The Anisoptera are further sub-divided into 2 families and these 

 again into 7 sub-families ; the Zygoptera are sub-divided into 2 families 

 and numerous genera without any intervening sub-families. 



Suborder I.— ANISOPTERA. 



Lnago : the hind-wing differing from the fore by reason of its broad anal 

 field. Between the 7th and 8th nervures, a complicated-shaped trigone 

 and hypertrigone. Running from the trigone, between the 7th and 8th 

 nervures, a distinctly limited discoidal field. Eyes variable. Labium 



