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Bnti6b 1bi?5racbnit)a^* 



By Charles D. Soar. Part VII. Plate III. 



IN the present paper we purpose considering two somewhat 

 similar genera of Hydrachnidce, the first to which we shall 

 direct attention being the Genus Limnesia (Koch). 

 1842. — C. L. Koch, Ubersicht des Arachnidensy stems, p. 3, p. 27. 



Mites belonging to this genus are characterised as having the 

 body soft-skinned ; legs well-supplied with swimming hairs ; fourth 

 pair of feet without claws ; three genital suckers on each side of 

 the genital fissure ; epimera in four groups ; palpus not chelate ; 

 mandibles in two portions ; eyes wide apart. 



The members of this genus differ from any others which have 

 been previously considered in being without ungues to the tarsus 

 of the fourth pair of legs ; it is a genus easily recognised when 

 once seen. There is only one other genus that is likely to be 

 mistaken for it, viz., Teutonia (Koenike) ; but the difference is 

 very observable when once it has been pointed out. We shall 

 describe the genus Teutonia later on in this paper. All the species 

 of Limnesia with which I am acquainted show very little difference 

 in structure, the male and female being very much alike, the only 

 remarkable feature being the shape of the genital plates, as shown 

 in Plate III., Figs. 3 — 5. In size the males are a Httle smaller than 

 the females, but they do not possess that peculiar spur on the 

 fourth pair of legs, so commonly met with in Arrenurus, AxoJia, 

 and others, to which attention has been drawn in previous papers. 



There are several British species ; some are very common, and 

 exhibit a great variety of colours, ranging from deep red to pale 

 yellow ; they can be found almost anywhere in ponds, lakes, or 

 rivers. They will live a long time in confinement ; I have fre- 

 quently kept them, both in summer and winter, for several months 

 at the time, but I have not been so fortunate as to have any ova 

 deposited either in the tanks or in the tubes in which I have 

 kept them. 



They are very much like the spider family in the way they prey 

 on the other life in the same tank, and when that is exhausted 



