I 



1906-1907.] British Hydrachnid(Z : The Genus Fiona. 385 



Three swimming-hairs to distal end of patella. (Plate XL., 

 figs. 73-78.) 



Localities. — Not common. 



17. Fiona conglolata, Koch. 



Female. — About I'lO mm. in length, brownish-yellow in 

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

 marked with rather coarse lines. Epimera, palpi and legs 

 generally of a pale -blue colour, with the tarsi sometimes 

 inclined to red. Locality no doubt has a great deal to do 

 with the intensity of the colouring ; some specimens taken 

 on Wimbledon Common were very decided in colour, while 

 others taken at the same time from the Warren, Folkestone, 

 were very faint. Palpi thicker than trochanters of first pair 

 of legs, and strong in structure; two hair pegs on inner 

 flexor edge of fourth segment of each palpus rather close 

 together. Acetabula nearly all free on the ventral surface, 

 only one or two being on hair plates ; arrangement of 

 acetabula very irregular. Legs well supplied with bristles 

 and swimming-hairs ; claws rather prominent. First pair of 

 legs measure about 0*80 mm.; fourth pair about 1"02 mm. 



Male. — Measures about 0'60 mm. Acetabula on plates 

 which surround the anus, and not free on the body surface as 

 in the case of the female. Width across the plates 0"32 mm. 

 Claws on third pair of legs very short and close to tarsi. 

 Patella on each of fourth pair of legs, with three swimming- 

 hairs at distal end. (Plate XLL, figs. 79-84.) 



Localities. — Very common. 



18. Fiona stjordalends, Sig Thor. 



Female. — About 1"40 mm. in length. Colour yellow with 

 dark -brown markings. Genital plates tongue -shaped, with 

 from 20 to 25 acetabula each, all nearly of one size. 



Male. — About 1*20 mm. in length, with same colouring as 

 female. Seminal pocket trefoil-shaped ; genital plates, with 

 about 25 acetabula on each plate. There is a hook-like 

 claw to tarsus of third pair of legs, but not so prominent 



VOL. V. 2 c 



