PARASITIC ON ANTS. 431 



creature, i.e. its longitudinal dorsal axis, is higher in 

 level than in parts nearer the margin, and forms an 

 irregular triangle of rough chitine. A broad chitinoua 

 plate or ridge projects on each side above the second 

 leg, and between that and the third, evidently for their 

 protection ; it is probably flexible at the will of the 

 creature, as in the genus Oribates. 



The sternal surface has strongly marked depressions 

 for the reception of the legs. The coxae of the first 

 pair of legs are largely developed, flattened, almost 

 touch in the median line, and nearly conceal the mouth, 

 as in the typical Uropodas. The genital opening of 

 the male is rather large, round, and placed centrally 

 between the coxae of the second pair of legs. The 

 female appears only to be distinguished from the male 

 by being more strongly chitinised, and by the con- 

 spicuous valval plate which occupies the whole space 

 between the coxae of the second and third pairs of legs 

 and extends beyond both. 



The nymph is less square in the abdomen than the 

 adult, and the border of hairs is absent ; the margin is 

 somewhat undulated, the concave undulations being so 

 placed as to give free action to the legs when raised ; 

 the central depression of the abdomen is far less 

 marked than in the adult; a slight ridge runs all 

 round the dorsal surface a little within the margin ; 

 four ridges, two anterior and two posterior, run from 

 the circumscribing ridge to a raised ellipse in the centre ; 

 there are not any plates for the protection of the legs, 

 and the coxae of the first pair are not flattened as in the 

 adult. 



This mite lives in the nests of Formica /lava. 



