I 



1906-1907.] British Hydrachnida : The Genus Fiona. 383 



inclined to crimson, with yellow at both anterior and posterior 

 margins. All chitinous parts of the same crimson red. 

 Colour of each segment of the legs inclined to yellow at 

 the distal ends, more particularly in the tarsi. Legs strong, 

 and well supplied with swimming-hairs. Palpus rather large, 

 with two hair -pegs on flexor edge of fourth segment. 

 Palpus about \\ times as thick as trochanter of first leg. 

 Genital plates more or less disc-shaped, each with from 25 

 to 35 acetabula. 



Male. — About 1-90 mm. in length; similar in colour to 

 female. Seminal pocket trefoil-shaped. Claws on third pair 

 of feet very peculiar, being hooked and partly screwed round. 

 (See fig. 53.) Distal end of patella with six or seven hairs. 

 (Plates XXXVI and XXXVII., figs. 48-58.) 



Localities. — Common. 



13. Fiona noclata, var. immimtta, Pier. 



Same characteristics as above, only much smaller, and 

 yellow in colour, with brown markings. The female measures 

 about 1-60 mm. in length, and the male about 1-20 mm. 

 Pigs. 51 and 56 are drawn to show the actual difference in 

 size when compared with figs. 49 and 55. (Plate XXXVL, 

 fig. 51, and Plate XXXVII., fig. 56.) 



Localities. — Lincolnshire and Suffolk. 



14. Fiona carnea, Koch. 



Female. — About 2.10 mm. in length, of a dull dirty brown 

 colour, with dark-brown markings on dorsal surface. Mal- 

 pighian vessel scarcely visible. Genital plates disc -shaped, 

 with from 18 to 24 acetabula on each plate. Palpi very 

 small and weak, with two hairs wide apart on flexor edge of 

 fourth segment. 



Male. — About 1*55 mm. in length. Similar in colour to 

 female. Palpi small and weak. Seminal pocket cherry- 

 shaped, genital plates with about 15 acetabula each. Nine 

 swimming-hairs at distal end of patella of fourth leg. (Plate 

 XXXVIII, figs. 59-65.) 



Localities. — Lincolnshire, Norfolk and Suffolk. 



