388 British Hydrachnidcs : The Genus Fiona. [Sess. 



The legs have nothing remarkable about them. Palpi strong 

 and about \\ times as thick as trochanters of first pair of 

 legs, with two hairs on fourth segment, one being on a very 

 strong hair peg on flexor edge. Genital plates irregular disc- 

 shaped, with from 10 to 16 acetabula each, one or more being 

 much larger than the others on each plate. 



Male. — About I'lO mm. in length; about same colour as 

 female. Seminal pocket heart-shaped, with the margins 

 almost extending out into the trefoil form we have noticed 

 in some others ; about 1 2 acetabula on each plate. Four 

 swimming -hairs on patella of fourth leg. (Plate XL VI., 

 figs. 112-118.) 



On account of its beautiful form and colouring, I propose 

 to call it Piona elegans. 



Localities. — Norfolk Broads, common. 



[Chart 



