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Show 5 6 8 OX BRITISH MITES OF THE FAMILY ORIBATID^E. [Dec. 12, Claws monodactyle. Pseudostigmatic organs long and filiform. Nymph and larva unknown. This fine species is closely allied to iVr. targionii Berlese, but may be distinguished from it by the much longer, wavy, ton-pectinated hairs on the notogaster. The apophyses from which these hairs spring are very small, while in i\r. targionii they are exceedingly conspicuous. A single example was sent by Mr. W. Evans, taken at Loch Gaily, Fife, in May 1 9 0 5 . Another specimen was found by us in Sphagnum from Blairgowrie, Perthshire, in November 1 9 0 5 . This species, even more strongly than N. targionii, recalls Hermannia bistriata, and in these three forms the two genera approach one another very closely. N o thrus tectorum Berlese. (Plate XX. fig. 4.) (Hypocthonius tectorum Berlese, Acari Myriapoda et Scorpiones etc., fasc. 7 8 , no. 8 , 1 8 9 6 .) This species, which we at first regarded as new to science and which may be easily recognised from the figure (PI. XX. fig. 4), is no doubt identical with the Hypocthonius tectorum of Berlese. That araclinologist has, we believe, been misled by an apparent segmentation artificially produced by slight pressure in mounting. We have examined many living specimens, and specimens mounted without pressure, and these present no trace of segmentation; but we find that a transverse furrow (varying slightly in position and width) is readily produced in the soft integument when the cover-slip is allowed to press somewhat heavily upon it. The species must therefore be removed to the genus JVothi'us, to which it undoubtably belongs. Not rare in moss from walls and liouse-roofs at Grantchester, Cambridge. N othrus orassus, sp. nov. (Plate XX. fig. 5 .) Length 5 0 0 fu. Colour light yellow-brown. Integument smooth and very imperfectly chitinised. Claws tridactyle. Pseudostigmata fairly large but not very projecting. Pseudostigmatic organs spindle-shaped, often directed backwards, and rather large. Genital and anal plates large and close together. An aquatic or amphibious species occurring in Sphagnum in heath-pools near Bournemouth, in company with N. glaber and N. monodactylus. Of the not very well-defined genus Nothrus the five species tectorum, tardus, glaber, monodactylus, and crassus form a compact group, agreeing in the rounded form of the abdomen and in their very slight degree of chitinisation. Tectorum and tardus are terrestrial species, while the other three always occur in or near water, and in glaber and monodactylus the pseudostigmatic organs are absent. |