377 



SOME BRITISH EARTHMITES. 



Tsotnbidiidae {Continued from page 336). 



C. F. GEORGE, 

 Kivton-in-I^indsey . 



Tromhidium fuliginosum Hermann. 1804. 



This mite appears to be the next best known species of this 

 family, it is in size rather smaller than holosericeum, not so 

 square in figure, but longer in proportion to its width, also the 

 posterior edge is convex outwards, and not emarginate. In 

 colour, it is rather dull red, and does not possess that silky 

 lustre, which makes holosericeum so handsome in a bright 

 light ; the skin is covered with a dense pile of hair, or papillae, 

 each one is rather thickly pinnate, but is not clubbed or curved 

 as in holosericeum (figures e. g. and h.) They should be 

 examined by a fairly high powder. The eyes are long pear- 

 shaped, and each one is furnished with two ocelli. 



The palpi have the second joint rather slender, but in other 

 respects much like those of holosericeum. The legs also are 

 similar, but differ in having at their distal end, between the 

 claws, a very beautiful and curious foot pad, reminding one of 

 the feet of certain flies (fig. c). 



The female genital aperture is furnished within with six 

 genital discs, three on each side, well shewn in Mr. Soar's draw- 

 ing (fig. F,) but perhaps the most remarkable structural arrange- 

 ment is the chitine of the crista, which is somewhat shield 

 shaped, and has three perforations, the lower one large and oval, 

 in the centre, and the two upper ones rather small, one in each 

 corner (fig. d). It is rather difficult to describe so as to give a 

 clear idea of its structure, and should be carefully examined 

 under the microscope. Professor Sig Thor gives an enlarged 

 figure of it in his paper, and considers the mite to be a variety 

 ■of fuliginosum, and calls it " var. norvegicum." Professor 

 Ivar Tragardh also, in his pamphlet on the results of the 

 Swedish Zoological Expedition to Egypt and the White Nile, 

 1901, gives a similar figure from a mite found under a stone near 

 Cairo, to which Professor Berlese has given the name of Allo- 

 ihrombium pergrande. Miss and Mr. Soar found this mite 

 at Putney ; Mr. W. Evans of Edinburgh found it at Dudding- 

 ton Loch ; and Miss Nicholson in Gloucestershire, to whom I 

 am indebted for specimens. The mite is evidently widely 

 distributed. 



1908 October i. 



