SIE J. LUBBOCK ON ANTS, BEES, AND WASPS. 387 



in the middle, the central point being forward ; at the sides of, 

 but not in, this depression, are two chitinous blocks which seem 

 to form a starting-point for the ridges. Anterior to this depres- 

 sion the central portion of the 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 chitinous 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 ia 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 TJropodas. The 

 genital opening of the male is rather large, round, and placed 

 centrally between the coxeb of the second pair of legs. The 

 female appears only to be distinguished from the male by being 

 more strongly chitimzed, and by the conspicuous 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 pro- 

 tection of the legs, and the coxae of the first pair are not flattened 

 as in the adult. 

 This mite lives in the nests o£ For mica flava. 



