^y8 British Hydrachnidce : The Getius Fiona. [Sess. 



1. Fiona fitscata, Herm. 



Female. — Body about 1"20 mm. in length, of a dark red 

 colour, with black markings. Malpighian vessel very little 

 lighter in colour than other parts of the body. Legs long and 

 well supplied with swimming - hairs. Eetractile claws very 

 prominent. Colour of legs red like the body, but a little 

 brighter in tone. Palpi rather small and insignificant, the 

 flexor edge of the fourth segment having 2 papillae with seta3 

 placed a little way apart, one behind the other. Genital 

 plates sickle-shaped, each with from 8 to 12 acetabula, none 

 being free on the ventral surface. 



Male. — About 0'84 mm. in length, generally of a lighter 

 colour than female, with a much lighter-coloured Malpighian 

 vessel, and the body rather broader in shape at the posterior 

 margin. The third pair of tarsi have the distal end rather 

 thickened or broadened and a strong claw (Plate XXX., fig. 5). 

 The fourth leg has the usual shaped patella segment, with 

 three swimming-hairs at the distal end. The genital area is 

 composed of a trefoil-shaped seminal pocket with plates on 

 each side, each plate with from 8 to 12 acetabula. 



Plate XXX., figs. 1-7. Pigs. 1 and 2 are drawn to same 

 scale as all the other body figures. 



Localities. — It is a very common mite, and when found it 

 is frequently in large numbers. 



2. Fiona laminata, Sig Thor. 



This is very closely related to P. fuscata, Herm., and 

 may be only a variety of that mite. It is a little lighter in 

 colour than P. fuscata, and measures 1'50 mm. in length. Its 

 great difference is in the genital plates, which are much more 

 spread out than in P. fuscata, and have from 12 to 20 aceta- 

 bula each. The specimen from which my drawing was made 

 had IG on each plate. (Plate XXXI., figs. 13, 14.) 



Male. — Not taken. A male was taken with the female, 

 and it may prove to be a male P. laminata, but I should not 

 like to record it as such at present. It is very like P. fuscata, 

 but the tarsi of the first and second pair of legs are longer and 



