314 BRITISH HYDRACHNID^. 



1880. — Diplodontus filipes, Newman, Sveriges Hydrachnides, p. 108, 



Tab. XIII., Fig. 3. 

 1882. — Diplodontus filipes, Haller, Hydrachniden des Schweiz, p. 47. 

 1885. — Diplodontiis filipes, Krendousky, HydracJmidcE of Russia, 



p. 123, Figs. 16 — 20. 

 1896. — DipJodontus despiciefis, Koenike, Farschungolerischte aus der 



Biologischen Station zu Flofi. 



The first time I made the acquaintance of this Hydrachnid 

 was at the Warren, Folkestone, in July, 1894; it is a very beautiful 

 mite. The body is an ellipse in shape ; sometimes it is more 

 rounded than at others ; it also varies very much in size, some 

 females being quite twice the size of others ; its average length is 

 about 5/60 of an inch. The colour of the body varies very much, 

 some being a brilliant red, whilst others are of a dirty yellow, and 

 all intermediate shades. The whole of the surface of the body is 

 covered with small papillae. The dorsal surface is also strongly 

 marked with a number of brown patches, sometimes radiating from 

 the centre, and at others apparently in confusion and running in 

 all directions. Eyes four, two showing plainly on the dorsal 

 surface, and two on the ventral ; the upper pair project and stand 

 out in bold relief like glass beads. The legs are not very long, 

 but are well supplied with swimming hairs ; all the tarsi have claws. 

 The colour also varies very considerably. I have found some with 

 the legs of the same brilliant colouring as the body, whilst the legs 

 of others have hairs of a bright yellow ; so marked has been this 

 distinction of colour in some cases, that I at first thought I had 

 found a distinctly different species, but the structure in all cases 

 has been identical. The palpus is chelate (see Fig. 5). In the 

 larger specimens the mouth organs are so far under the body that 

 the palpi cannot be observed from the dorsal side, but in the 

 smaller specimens the last joint only can sometimes be seen. 

 The genital plates are close up to the genital fissure, and are 

 covered with a great number of raised dots. These dots are very 

 small, but they are exceedingly numerous. I can distinguish no 

 great distinctive difference in the sexes, except that which is seen 

 in the genital fissure, as shown at Figs. 7 and 8, Plate XVI. 



These interesting little creatures will live well in a tube at 



