560 IVAR TRAGARDH 



But it is astonishing to find that Jacot in 1930 makes such an imper- 

 fectly described species as A^, concentricus Say the type of a genus. 



It is true that jACOT has had the opportunity of examining specimens 

 determined by Banks as N. concentricus, and has added some details to Banks 

 description. But this does not throw any light on the original N. concentri- 

 cus Say. 



It would seem that Neoliodes is quite sufficiently characterized by its re- 

 markable shape, the covering of the four larval and nymphal skins with their 

 peculiar structure etc. Nevertheless there is one important feature which appears 

 to have been completely overlooked by all previous authors, 



I refer to the peculiar shape of the hypostome and the maxillae. 



In fig. 14 I give a detailed drawing of the hypostome and maxillse of 

 Neoliodes Bdckstrdmi which shows that at the base of the maxilla; there is a 

 pair of transverse, narrow plates the base of which is concealed underneath 

 the edge of the hypostome, and which carry two pairs of hairs and have a 

 reticulated sculpture. 



Such a feature is, as far as I know, hitherto unique amongst the Oribatei 

 as yet known, but occurs also in Plateremoeus vestitus from Juan Fernandez 

 (compare fig. 23). 



The investigation of material o{ Neoliodes farinosus (C. L. KoCH) from 

 Sweden has enabled me to correct some mistakes made by Berlese (fig. 3, 

 pi. 42). It is true that the anterior margin of the hypostome has a transversal 

 line as drawn by B. but the hairs are inserted in front of this line, on the 

 marginal shield formed by the line. In front of this B. delineates a semilunar 

 transverse plate. In reality there is not one shield, but the bases of the maxillae 

 are thicker and more darkcoloured so that they appear to be two shields. 

 Further these basal portions of the maxillae, which are hinged on to the anterior 

 edge of the hypostome, which covers their base, have two pairs of hairs, not 

 one as dehneated by Berlese. These two pairs of hairs have a very charac- 

 teristic shape and position; one pair, inserted near the median edge is small 

 and points straight forwards, the other is large and inserted in the postero- 

 lateral angle, underneath the anterior edge of the hypostome, is curved sharply 

 inwards towards the middle and S-curved. 



In all these respects Plateremaeus agrees with Neoliodes as does also 

 Cymberemaeus, where, however, the anterior margin of the hypostome projets 

 as a free thin blade which covers half the maxillse. 



3. Neoliodes Backstromi n. sp. — Figs. 11 — 19. 



Length 1330 [jl; width 910 (x; width of propodosoma 420 [i. Length of 

 shields: 410 [jl; 550 [x; 680 [i; 800 [jl. 



Colour very dark brown. 



Propodosoma (fig. 13) with a large dark coloured, hood-shaped projection 

 which occupies the whole anterior part as far as to the excavations surrounding 

 coxae I and extends backwards to a level with the pseudostigmata. It is through 

 a narrow transversal ridge of even width throughout divided into two portions. 



