British Orihatidse. By A. D. Michael. 227 



Kirton Lindsey, was doing the same thing. I communicated to 

 him that I was preparing a paper on the subject to be submitted to 

 this Society, and he at once placed his observations and specimens 

 at my disposal, a piece of generosity which I desire most gratefully 

 to acknowledge. I have endeavoured to mention his observations 

 as they occur. My searches have been made during the past 

 twelve months, near Tam worth, in Warwickshire ; at Wandsworth, 

 in Surrey ; Epping Forest ; and the shores of Loch Maree and 

 Loch Ewe, in the Eoss-shire Highlands ; Epping being more 

 thoroughly hunted than the other places. 



Mr. George has collected entirely at Kirton Lindsey, in 

 Lincolnshire. 



I am aware that the ' Transactions ' of this Society are not the 

 place to monograph a family of British Arachnida, although of 

 microscopic size, nor would the number of plates which can fairly 

 accompany a paper like this enable one to do so, even if twelve 

 months' searching were sufficient for the purpose, which is far from 

 being the case ; but I have thought that our observations might 

 possibly be of sufficient interest, and would contain sufficient 

 entirely new matter, to excuse my occupying a little of your time. 



The plan I have followed is to give first a short summary of 

 the principal distinctive characters of the family and a reference to 

 the leading foreign bibliography (there is not any English) ; then 

 such observations as to general matters as I have to submit ; and, 

 finally, to give a list of the species found, with any observations as 

 to each species which I have thought new and interesting, and also 

 details of such larvae and nymphs, which had not been before 

 observed, as I have been able to rear, so as to be certain what 

 species they belonged to. 



Distinctive Characters of the Family. 



Taking for granted the distinctions common to all Acarina, the 

 Oribatidte are formed into a strongly marked group by the 

 following characters, viz. : — 



1. A hard chitinous exo'skeleton, as in a beetle ; it is this 

 resemblance that has given origin to the name of beetle mites. 

 The chitine covers every external part of the j)erfect creature, and 

 is very hard, but extremely brittle and entirely devoid of elasticity, 

 so that on any pressure it breaks into fragments ; it is always black 

 or brown. 



2. The form of the stigmatic and tracheal system, which is 

 peculiar, consisting of two hard, more or less projecting, stigmata, 

 of a short tubular or trumpet shape, one at each side of the 

 cephalothorax near the juncture with the abdomen (but varying a 

 little in position) ; below each of the stigmata is an air sac, and 

 some long filiform tracheae supplying the body, and from inside 



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