173 



THREE WATER-MITES NEW TO BRITAIN. 



By George P. Deeley. 



Read October l$th, 1907. 



Plate 13. 



Thyopsis cancellata, Protz. 



This mite is of a deep red colour with dark, almost black, 

 markings. 



Body a broad oval. 



Length about 1 '54 mm., breadth 1*33 mm. 



The dorsal surface is hard, with a large number of spots more 

 or less square in outline, and the remaining area covered with 

 fine green markings. The effect is to cause the back to look 

 like a perforated plate. Eyes distinct and wide apart. Edge of 

 body when focussed with a g-in. objective appearing as if covered 

 with a fringe of very fine hairs. Epimera in four groups, and 

 small in proportion to size of body. Legs — 1st pair about '7 mm. 

 long, 4th pair 1*15 mm., all supplied with a large number of 

 short thick spines or hairs. Colour a light red, and, together 

 with the epimera, covered with fine green markings. Claws to 

 all feet. Palpi thin, 0'4 mm. long, 2nd segment being thickest, 

 furnished with several strong hairs, and a small peg on inner 

 edge of last segment but one. Genital area composed of two 

 plates, with three acetabula on each plate, one at forward end 

 and two at posterior. Inner edge of both plates fringed with 



