344 BRITISH ORIBATID^E. 



leaf-like, arranged longitudinally in the median line of 

 this skin. Round the lateral and posterior margins of 

 each nymphal skin are a series of sixteen (or fourteen 

 in some young skins) large, flat, chitinous, brown pro- 

 jections of very singular form ; each corresponds 

 bilaterally with its fellow on the opposite side of the 

 body, but no two pairs are alike. All, except the hind 

 pair, are comparatively narrow where they spring from 

 the abdomen, but each expands suddenly to a head, 

 which is trifid in the hind pair, the central cusp being 

 the smallest. As the projections get further forward 

 they lose their trifid form, the central cusp coalescing 

 more and more with the anterior, and the posterior 

 cusp becoming larger and more elongated, until the 

 projection at the antero-lateral angle is reached, 

 which again is trifid like the posterior. From the 

 central cusp of each of the hind and anterior projec- 

 tions, and from the portion of the coalesced anterior 

 and central cusps which represents the central in the 

 other projections, springs a strong spine, which is 

 straight in one or two cases, but generally singly or 

 doubly curved. Each spine is bordered on each side 

 by a broad, thin, transparent membrane, or chitinous 

 expansion, which follows the line of the spine and is 

 supported by it, and which is elegant and sweeping 

 in curvature, broadest about the middle or near the 

 proximal end, and pointed at the distal end, giving 

 the whole structure a leaf-like appearance, the spine 

 being the mid-rib of the leaf. This effect is increased 

 by a number of spinules which spring from the central 

 spine and extend sometimes to the edge of, or slightly 

 beyond, the membranous expansion ; or sometimes stop 

 a little short. The central spine, and some of the 

 spinules, bear short sharp thorns or spikes pointing in 

 various directions, but chiefly upward. The projec- 

 tions are radial from the abdomen, but the leaf-like 

 processes are not ; the hind pair are in the line of the 

 projections, and point backward; those further for- 

 ward are set at various angles to the projections from 



