108 C. D. SOAR OX TWO NEW BRITISH WATER-MITES. 



of the same genus. As regards measurements, it is a little less 

 than Mideopsis orbicularis, being as follows : length of body, 

 0-80 mm. ; breadth, 0*72 ; first leg, 0.48 ; genital cleft, 0'22 mm. 

 in length. The great points of difference are in the thickness 

 of the legs and the thickness and shape of the palpi. The legs 

 in Mideopsis orbicularis are very thin and slight; in this mite they 

 are strong and thick, as will be seen by comparing the drawings 

 of the two species. 



The fourth segment of the palpus is very strong, with two 

 curved, strongly formed spurs on the flexor side of the palpus. 

 The two specimens taken proved, fortunately, to be male and 

 female, so I am able to give a drawing of the genital plates of 

 each. The male is more oval in outline than the female, but in 

 all other respects the structure is the same. On account of the 

 great thickness of the legs compared to the other species I propose 

 to call it Mideojisis crassipes. 



Explanation of Figs. 1 and 2. 



Fig. 1. 



a. Pseudofeltria scourfieldi, female, ventral surface. 



b. „ ,, ,, dorsal surface. 



A 1 & . -J. 



a. Mideopsis crassipes, dorsal surface of male. 



b. ,, ,, ventral surface of male. 



c. ,, „ palpus of male. 

 > ? . „ „ first leg of male. 



e. ,, ,, genital plate of male. 



/'. ,, ,, genital plate of female. 



Jo-am. Qaclxtt Microscopical Club, Scr. 2, Vol. IX., No. 55, November 1004. 



