508 BRITISH ORIBATID^. 



or less [oblong space in the median line is slightly- 

 depressed ; it is bordered on all sides by a conspicuous 

 raised ridge, which is generally somewhat curved ante- 

 riorly and posteriorly, more straight laterally ; but 

 there are two slight constrictions in the lateral ridge 

 (on each side of the body) ; near these constrictions 

 the two lateral ridges are joined by a thinner trans- 

 verse ridge, generally curved, and a diagonal ridge 

 runs outward from each outer corner of the oblong. 

 Three small chitinous apophyses, each bearing a very 

 small, curved, spatulate hair, stand horizontally out- 

 ward from the outer edge of each of the lateral ridges, 

 the first placed just behind the junction with the ante- 

 rior diagonal ridge and the others in the two constric- 

 tions ; the first and second of these apophyses are nearer 

 together than the second and third. A similar apophysis 

 and hair project from the hinder edge of the postero- 

 diagonal ridge. Outside the lateral ridges of the 

 above-described oblong the abdomen is decidedly 

 concave ; it then rises again, forming a broad, raised, 

 rounded margin, the extreme edge of which is not the 

 highest part ; this raised edge bears a few irregular, 

 more or less transverse ridges, and also (on each side 

 of the body) three small chitinous apophyses, each 

 bearing a short, curved, spatulate hair ; the apophyses 

 do not project beyond the lateral margin of the body. 

 The pore of the expulsory vesicle is near the last of 

 these apophyses but a little closer to the median line. 

 There are six similar apophyses and hairs by the pro- 

 gaster. All the hairs springing from apophyses on 

 this creature are thick and covered with villous pro- 

 cesses or membranous fringes. Genital and anal plates 

 large and close together, the former the wider and 

 almost pentagonal ; the latter longer and coming to a 

 point posteriorly. 



Nymph. 



I believe the creature here described to be the nymph 

 of N. horridus ; but, as at the time when I bred it I 



