British Orihatidse. By A. D. Michael. 185 



tectum, surrounds the depression that receives the coxa of the first 

 leg. Interstigmatic hairs long and setiform, stigmata hidden below 

 the tectum. 



Legs with a whorl of fine hairs on the distal end of each joint, 

 except the tarsus, which is sparsely clothed with similar hairs. 



Abdomen rounded on the anterior margin, imiformly polished, 

 and bearing two extremely fine hairs on the ventral edge of the 

 hind margin. 



Larva and Nymph, PI. Ill, Figs. 1, 2, 3. 



If the perfect form be a somewhat ordinary looking creature, 

 this cannot be said of the larva and nymph, which are amongst the 

 most marvellous in the whole range of Acarina. A description of 

 the nymph will serve for both, because it carries the cast noto- 

 gastral skins, which, in the immature stages of the species, is the 

 whole of the creature that can be seen on the dorsal view. 



Cephalothorax short, broadly conical, and plain ; it carries two 

 pairs of fine hairs, one near the point of the rostrum, and the other 

 on the anterior edge of the vertex. 



Legs rather short, of nearly uniform thickness throughout ; 

 tarsi densely clothed with hairs ; each hair springs from a short 

 apophysis; similar hairs, but thicker and fewer, are found on the 

 other joints of the legs. As far as the dorsal aspect is concerned, 

 both cephalothorax and legs may be neglected altogether, the 

 former being completely hidden, and of the latter only the tips 

 of the tarsi of the first pair being visible, sometimes not even 

 these. 



Ahdonien elliptical, major axis about half as long again as 

 minor in the young larva, but tlic two almost the same length in 

 full-grown nymph. The edge of the ellipse is not even, but is more 

 or less concave or straight between each pair of the apophyses men- 

 tioned below. The cast notogastral skins are carried concentrically. 

 The median portion of the back is strongly arched, and has waved 

 transverse lines or wrinldes, very minutely dotted. The margin is 

 slightly raised. The nymphal skins, where not covered by the larval 

 one, are finely reticulated. Hound the margin of the creature 

 are twenty apopliysos ; eight of these are rather crowded together 

 on the anterior portion, the others are more evenly distributed, but 

 those at the sides are furthest apart. Sixteen of these apophyses 

 are more or less expanded at the base, and in most instances have 

 three points, the lateral ones thin, Hat, sharp, and often abortive, 

 the centre stout, cylindrical, truncated, and carrying a remarkably 

 large i)ahnate or spatulate hair or scale (Plate III. Fig. 3). standing 

 quite free from the body ; the sha})o of these scales is much like that 

 of an ordinary scale of the lepidoptorous species, Lycctui Argus, 



