122 DRAGONFLIES [CH. IV 



bluish-green with narrow yellowish intersegmental rings. 

 Length of $ 3336 mm., $ 3436 mm. Expanse of 

 wings $ 3640 mm., 9 44 48 mm. 



(73) 76. A. mercuriale, Charp. with black mark shaped like 

 symbol for the planet Mercury upon 2nd abdominal 

 segment (a crescent, with horns turned forward, stand- 

 ing on a "mushroom" whose stalk joins black ring 

 behind). Pear-shaped blue spot behind eyes nearly 

 circular in both sexes. $ abdomen black-bronze : ring 

 between 7th and 8th, and 8th and 9th segments clear 

 blue. Length of <J 2731 mm., $ 2931 mm. Ex- 

 panse of wings ( 3135-5 mm., $ 35 39 mm. [Rare. 

 New Forest.] 



(72) 77. genus Enallagma. Abdomen and nodal sector as in Agrion. 

 Pterostigma entirely black, or with pale centre, alike on 

 both wings. $ with apical ventral spine on 8th abdo- 

 minal segment. 



1 species : E. cyathigerum y Charp. With characters of the 

 genus. 



