2i6 Britisli Dragonflies. 



]Vi)igs broad at centre ; rich metallic blue, like the 

 rest of the insect (deep brown in some lii^hts; ; apex 

 and base brown and somewhat transparent ; meshwork 

 fine. Ptcrostigina absent. Abdouicu long, slender, 

 cylindrical, deep metallic blue ; a trifle swollen at 

 eighth and ninth segments. Aiuii appendages black ; 

 upper rather long, spiny, flattened, and approaching 

 posteriori)', turned slightl)' downwards ; lower appendages 

 shorter, flattened, approaching at tips, turned upwards. 



Female Imago. 



In the female the general ground-colour instead of 

 being blue is deep metallic green, which on the hinder 

 part of the abdomen changes to a decided coppery tint ; 

 a }'ellow mid-dorsal line extends along segments 8, 9, 

 and 10, the tenth being keeled. Wings narrower than 

 in the male ; in general russet, costal margin green. 

 Pterostiguia white, small, elliptical, about I mm. long. 

 Ovipositor sharp, as long as the ninth segment, sheaths 

 reaching to the end of the tenth. Anal appendages 

 short, sharp-pointed, conical. 



Immature Colouring'. 



In the i/iale the wings are at first russet, much as in 

 the female. Soon a smoky blue tint appears, and 

 ultimately they become deep blue. This change of 

 colour was a cause of much confusion amongst the 

 older writers. The female colouring is at first clear 

 russet, but becomes somewhat darker with age. 



Variation. 



Unlike most British Dragonflies, C. virgo is subject 

 to considerable variation. The chief forms are as follow : 



