286 British Dragonflies. 



edged with bluish ; lower surface yellowish-green, with 

 black mid-ventral line. Anal appendages short, pointed, 

 dark. Ovipositor red, reaching about the end of the tenth 

 segment. Valves bluish-green. 



Immature Colouring. 



In reaching maturity a similar series of colour-changes 

 is passed through to that mentioned in the case of 



A. p/ile/ielliini. 



Variation. 



In the male the sides of the U on segment 2 are 

 sometimes separated from the base, so that the spot 

 consists of three lines. The blue spot on segment 6 

 varies in size, and the black spot on segment 9 is 

 sometimes quite divided so as to make two lateral spots. 

 The female sometimes has the green parts altered to a 

 decided bluish tint. The pale circlet at the sutures 

 may on some segments develop into basal bifid spots, 

 and the bronze spot on segment 2 take the form of the 

 mercury-spot in the male of A. Dierciiriale, in which 

 case it is difficult to distinguish the insect from a female 

 of A. pulcJielluvi, except by the hind-margin of the 

 pro thorax. 



Nymph (Fig. 50). 



In shape long and slender ; length, including caudal 

 lamellae, about 22mm. ; greatest breadth about 2"5mm. 

 General ground-colour yellowish-green, points and 

 markings reddish-brown. Head a flattened pentagon ; 

 transverse measurement about 4mm. ; longitudinal about 

 2mm. ; lateral edges sloping backwards considerably. 



