220 C. D. SOAR ON ATAX TAVERNERI. 



Colour : — 



A pale straw-yellow with darker markings on the dorsal 

 surface, very much the same as some species of A fax crassipes 

 MUller. 



Form : — 



A long oval truncated at the posterior margin, very much the 

 same as A. axissipes, for which, at first sight, it may easily be 

 mistaken, as, like this species, it has the two papillae, one at each 

 angle of the posterior margin. In this respect it also agrees with 

 Atax aculeatus Koenike. These two papillae project beyond the 

 body line, in some specimens more than others, and they are 

 common to both sexes. 



Legs :— 



Do not essentially differ from those of A. crassipes, except that 

 they are not so long in proportion to the length of body. The 

 first pair possess those powerful bristles or sword-hairs peculiar 

 to the members of this genus, and the second pair are much 

 longer than the first. 



Palpi :— 



Resemble those of A. figuralis Koch., except that on the third 

 segment Piersig has drawn a pectinated hair, which is absent in 

 the mite now before us, its place being taken by one which is 

 quite simple and sharp. 



Genital area : — 



In the female there are four plates similar to Atax crassij)es^ 

 but the discs are difierent, there being but two in each upper 

 plate and three on each of the lower. This arrangement is very 

 general, A. honzi, A. figuralis, and several others having ten 

 discs placed in similar positions. In the centre of the four plates 

 are two powerful spurs bent outwards, and outside the plates, 

 one on each side, are the papillae before mentioned. In the male 

 there are only two plates with five discs on each, and in a similar 

 position to the discs on the male plates of A. honzi Claparede 

 except that there is not so much space left on the plate itself at 

 its upper part. 



Locality : — 



Found in clear water at Highams Park, free swimming ; several 

 specimens were taken and also a few nymphs. 



I think the above is sufiicient to distinguish this creature from 

 other species of the same genus, and if my view is correct that 



