44 THE SCOTTISH NATURALIST 



The first pair of legs are shorter than the others, the 

 fourth pair being longest. This mite does not swim, so 

 there is a complete absence of those swimming hairs to be 

 found on other members of the family Limnocharida^. It has, 

 however, a very large number of short spines on the legs. 

 At the end of each leg is a double claw. Here the accessory 

 claw so often found in other species is wanting. 



The genital area lies between the fourth pair of epimera. 

 There is a fair-sized vulva, and protecting it are two flaps, 

 hinged at their outer edge. Anteriorly each flap is narrow, 

 but increases in size towards the posterior, where the inner 

 portion is cut off obliquely. There are three pairs of 

 acetabula one at the narrow anterior end and two at the 

 posterior end, which also carries a fringe of hairs. The anus 

 lies midway between the epimeral area and the posterior 

 body margin. 



Except for its smaller size, the male is not readily 

 distinguishable from the female. 



Thy as venusta has been taken in pools near Edinburgh. 



OtJier Scottish Species of Thy as. 



Two species have been taken in Scotland, T. extendens 

 George, and T. truncata (Neuraan). The former I took near 

 Edinburgh, and the latter at Tiree. T. extendens may be 

 recognised by the extended form of the capitulum, and 

 T. truncata by the very long rostrum. 



Lininesia fu/gida C. L. Koch. 



As a representative of the Hygrobatidae we may select a 

 fairly common mite, Lininesia fulgida, also to be met with 

 near Edinburgh. While we found in Thyas venusta a flattened 

 body, we find here one that has the dorsum highly arched 

 and the general body outline oval, without any shoulders 

 such as already noticed. The skin is smooth, without 

 papilla?, but, with a considerable magnification, a fine sur- 

 face ridging may be detected. Instead of the red of the 



