ACARINA FROM THE JUAN FERNANDEZ ISLANDS 597 



Pseudostigmata of ordinary size, not open cup- or trumpet-shaped but 

 with small orifices and a number of radial septa. 



Pseudostigmatic organ (fig. 88) with slender peduncle curved in an even 

 curve obliquely upwards, outwards and backwards, the head is small fusiform 

 and about ^/a as long as the peduncle. 



Hysterosoma. Dorsal side highly arched, the greatest height exceeding 

 slightly half the length; from thence the shield slopes more gently down- 

 wards towards the anterior margin and more steeply towards the posterior 

 margin (fig. 87). The outline is broadly oval and well rounded both at the 

 anterior and at the posterior margin. 



There are 5 pairs of slender hairs, arranged in two longitudinal rows as 

 far from the centre as from the sides, and one lateral pair on a level with the 

 anterior pair; at the hind margin there is a median pair of small hairs, curved 

 towards the middle and further laterally two pairs of very short and straight 

 hairs. 



Ventral side (fig. 90). Genital aperture small, oval, a little longer than 

 it is wide and placed far forward in the curve between epimera IV; genital 

 plates with a longitudinal row of 4 very small hairs along the median edge 

 and one pair of slightly larger hairs near the posterior margin. Anal aperture 

 large, almost twice as long and wide as the genital aperture, rectangular with 

 rounded angles, anal plates with two pairs of large hairs. Of the hairs of the 

 venter I have only been able to see 3 pairs flanking the anal aperture. 



Epimera I and II with well chitinized apodemata between them; epimera 

 III and IV fused together almost completely so that of the former only traces 

 are left in the shape of two irregular, faint, curved apodemata which start from 

 the middle of the hind margin of epimera II and curve outwards. Epimera IV 

 very large, their width being equal to that of epimera I and II together. Epi- 

 mera I and II with one pair of hairs, IV with two pairs, one near the median 

 line, the other near the posterior margin on a level with the anterior margin 

 of the genital aperture. 



The legs do not have any characteristic features. 



D. elegans is closely related to D. denticu latum (G. et G. Can), D. ca- 

 pense Paoli and D. megacephalum Berlese but is easily recognized, except 

 by its greater size, by the number and position of the dorsal hairs. 



Loc: Juan Fernandez. Masatierra, among mosses and leaves. 



16. Chamobates marginedentata n. sp. — Figs. 91 — 100. 



The numerous species formerly referred to the genus Oribata by Berlese 

 and Michael have during the last twenty years been divided off on a great 

 number of new genera, many of which have only been indicated by the nam- 

 ing of the type species of the genus, while others have only been characterized 

 by short diagnoses. 



A great part of these Oribatei have not yet been revised in the light of 

 the newly discovered important but minute features, such as the porous areae 



